Russia is believed to have implemented a lockdown on hospitals and medical centres in a 30-square-mile area following a feared plague outbreak.

Panic broke out when a female laboratory technician died and hundreds of people she came into contact with were placed in quarantine.

Darya Shipilova, 28, was reportedly working at the Irkutsk Anti-Plague Institute in Siberia when she was exposed to pneumonic plague.

Shipilova told medical staff she had accidentally broken a test tube holding live bacteria, according to news outlet Lyudi Baikala.

Now, foreign states have urgently tightened border health controls despite Russia insisting the anti-plague scientist died from 'unidentified pneumonia', rather than the suspected 'Black Death' bacterium. 

US secretary of state Marco Rubio said on Monday that Washington is monitoring reports of a plague infection but that it is not a 'cause for alarm'.

'There's very limited travel between the US and Russia, obviously, but like anything else, something like that gets out, it could quickly spread,' Mr Rubio told reporters before taking off on a visit to Iceland.

'So we're watching and monitoring it closely. I don't think it's cause for alarm, but it is cause for focus and a cause to just keep an eye on it. And we're doing that.'

The Putin regime is seeking to downplay Shipilova's death on October 1, yet widespread suspicion of a state cover-up is rapidly spreading.

It was revealed today that more than 60 colleagues of the young scientist will remain locked inside her Siberian research institute for days, sleeping on floors and chairs despite none testing positive for the plague. 

Up to five hospitals in and near Irkutsk are in 'epidemic' mode, according to reports, with hundreds of staff and patients not allowed to leave. 

City Clinical Hospitals No. 1, No. 3, and No. 10 and the Ivano-Matreninskaya Children's Hospital have been closed for a three-week quarantine, according to Lyudi Baikala.

Relatives of a woman giving birth at one of Irkutsk's maternity hospitals also reported to the outlet that it had imposed a quarantine. 

A source in the healthcare sector told the publication that Irkutsk doctors are 'openly talking about plague'.

Shipilova became unwell while on a field expedition with colleagues in Buryatia, beside Russia's eastern border with Mongolia.

She was admitted to hospital on September 29 and placed on a ventilator but died two days later in Shelekhov, a satellite city of Irkutsk.

She came into contact with roughly 200 people, who are now being monitored over fears of an outbreak.

Regional authorities are implementing a 'comprehensive set of anti-epidemic measures,' according to Maxim Modin, the mayor of the Shelekhovsky district in eastern Russia, near the Mongolian border.

The inpatient facility at the hospital where the lab technician was treated has been placed under quarantine, and several departments have stopped discharging or admitting patients, Modin added. 

Pneumonic plague causes a severe lung infection, with symptoms including fever, shortness of breath and coughing up blood, which typically begin to show between three and seven days after contact.

Fatalities from pneumonic plague drop to around 17 per cent if treated with antibiotics within the first 24 hours of infection.

However, the disease is almost always fatal if left untreated.

There have also been claims that Russian authorities are attempting to hide exactly what happened.

Reports claim that drugs used to treat the disease are running out in the region, leaving terrified residents piling into pharmacies and medical facilities demanding supplies.

In its only comment on the case, the Kremlin said the public should only trust updates coming from the official health agency.

'One should rely on official statements from Rospotrebnadzor rather than listening to various rumors and speculation,' Kremlin spokesman Dmitry Peskov said Monday.

The director of the Irkutsk Aluminum Plant (IrkAZ) in Shelekhov, Artem Fominykh, announced a mask mandate for factory employees on October 2, 'due to the current situtation in our region'.

He urged employees to seek immediate medical attention if they experienced any symptoms of illness. 

'Better safe than sorry - take precautions,' he said on his Telegram channel. 

Fominykh later said on October 4 that the mask mandate was a routine response to seasonal respiratory illness. 

The administration of Baikalsk, a city in the Irkutsk region, published a Telegram post on October 3 urging residents not to travel to Shelekhov.

'Due to unofficial information about a confirmed case of plague in a person in the city of Shelekhov, we ask you to limit visits to Shelekhov and nearby settlements until the circumstances surrounding this threat are clarified,' the Baykalsk city administration said in a post at 8.28am local time. 

It deleted the post two hours later, Lyudi Baikala reported. 

The national television channel REN TV also deleted five social media posts about the spread of plague in Shelekhov. 

It has come to light that Shipilova had personally worked with Yersinia pestis - the bacterium responsible for plague and the medieval Black Death - in laboratories at her workplace.

Ex-Soviet state Kyrgyzstan evidently doubts Moscow's assurances, as it has ordered heightened sanitary controls at all its border checkpoints over reports of the suspected plague case.

Officials said people, vehicles and cargo crossing its frontier were subjected to increased epidemiological surveillance.

A Health Ministry statement in the ex-Soviet republic said: 'These preventive measures were prompted by reports of a confirmed case of the plague in the Russian Federation.'

Uzbekistan was 'taking measures to prevent the importation and spread of highly dangerous infections'.

Kazakhstan's Health Ministry today made clear it is monitoring the Irkutsk situation, has taken 'preventive measures,' and is carrying out sanitary-quarantine controls at state-border crossing points.

It shares a 4,750-mile frontier with Russia.

Mongolia already has a high-alert status in its border regions with Russia.

In the US, a White House spokesperson said: 'The Trump administration is aware of the outbreak, is monitoring it, and is evaluating possible courses of action.'

The international precautions come despite Russia's Rospotrebnadzor health watchdog insisting since Sunday that there is no plague outbreak and declaring the situation in Irkutsk and nearby Shelekhov 'stable'.

Shipilova died in the early hours of October 2 after developing 'pneumonia of unknown aetiology,' according to officials.

If this was the case, it is unclear why strict quarantine has been imposed at her institute and several local hospitals.

Locals fear a cover-up with one saying: 'The more they reassure us, the more frightening it gets.'

Another said: 'They're lying just for the sake of lying, automatically. It's been like that for a long time.'

A woman, Inna, commented: 'There's a quarantine, but there's no disease.'

In March, Shipilova was named as an author of research into the sensitivity to antibiotics of Yersinia pestis taken from natural plague hotspots in Siberia.

Her work involved plague bacteria originating from Siberian regions including Altai as well as Mongolia and the Altai and experiments examining immune responses to infection.

The Russian media and Telegram channels had earlier claimed Shipilova accidentally broke a test tube containing plague bacteria while working at the Irkutsk Anti-Plague Institute of Siberia and the Far East on September 25, and then tried to hide the incident.

Her friends have angrily disputed this, saying she would have been aware of the need to seek urgent antibiotic treatment in the event of exposure to the plague.

A colleague's relative confirmed the lockdown at her institute.

'They locked everyone in isolation from Friday. More than 60 people - by Saturday not a single test had come back positive.

'And they are sleeping there - on the floor, on chairs. There are obviously no beds.

'They allowed relatives to pass food parcels through the checkpoint.'

Despite officials denying a hospital lockdown, a patient at City Clinical Hospital No.1 said: 'We are under full quarantine. None of our relatives are being allowed in. We are not being allowed out.'

Rospotrebnadzor said an expert biological-safety commission found no accident involving pathogenic microorganisms at the institute.

It also said extensive testing of Shipilova's samples found no microorganisms connected with her professional activities.

Yet almost 200 people identified as having had contact with Shipilova have been placed under observation.

A former colleague said her relatives believe doctors initially treated her as suffering from severe Covid, putting her on a ventilator, and alleged that antibiotics were administered too late.

The mystery has been fuelled by contradictory official statements.

Immediately after Shipilov's death, Russia's chief state sanitary doctor Anna Popova personally flew to Irkutsk to control the response to a 'particularly dangerous infection' - yet she has not spoken publicly.

Governor Alexey Tsydenov from neighbouring Buryatia initially referred to Shipilova as 'the woman who died from plague', before toning it down to say she 'may have died from plague'.

Mikhail Favorov, a senior Russian epidemiologist, dismissed the broken test tube explanation, according to the Moscow Times.

Favorov said: 'It's laughable. Someone working at the Anti-Plague Institute in Irkutsk wears a protective anti-plague suit.

'If you break a test tube, the likelihood of infection is actually very low. In short, it doesn't matter to the general public – they'll believe the 'broken test tube' story.'

He added: 'It's absolutely hair-raising. We will not be told what really happened.'

Pneumonic plague is one of three types of plague caused by the bacterium Yersinia pestis.

It is transferred as a result of breathing in airborne droplets from another person.

Septicaemic plague causes a blood infection as a result of flea bites or handling infected animals. 

Symptoms include internal bleeding and tissue turning black due to necrosis.

The third is the bubonic plague – also known as the Black Death and notoriously responsible for the Great Plague of 1665, which killed at least a third of the population of Europe at the time.

Irkutsk Governor Igor Kobzev has also been publicly quiet about the situation. 

On October 2, he released a statement describing the 'particularly dangerous infection' while reporting on a special meeting of the regional commission on sanitation and epidemic prevention.

On October 4, Kobzev made his first comments on Shipilova's death.

He did not refer to her by name but only as 'an employee of the Irkutsk Anti-Plague Institute'.

'Preventive measures are being carried out in the region under the strict supervision of Rospotrebnadzor,' the governor said.

'No microorganisms linked to the employee's professional duties were detected in samples taken from the patient,' Kobzev claimed.

'No reports of infectious diseases have been recorded among institute staff over the past 10 days. 

'All individuals who had contact with the patient have been identified, examined, and placed under medical observation involving daily laboratory testing.'

Moscow last registered a case of plague in 2016, when a 10-year-old child fell ill in the Altai Republic. 

Doctors believed that the boy may have caught the plague during a visit to the mountains, where the disease has been recorded in the region's marmot population. 

In 2013, a 15-year-old died in Kyrgyzstan after consuming infected marmot meat.

According to the Kyiv Independent, Russian authorities earlier this year tried to downplay another outbreak - a cattle epidemic that had swept parts of Siberia since February.

But veterinarians and independent journalists questioned that account, pointing to mass slaughter, village lockdowns, and secrecy more characteristic of a foot-and-mouth disease (FMD) outbreak. 

The suppression fueled resistance among farmers, confusion in affected areas, and renewed scrutiny of how Kremlin officials handle health crises - often prioritising control of information as much as the problem itself.