A Ryanair flight from London Stansted to Bulgaria is among multiple services reportedly disrupted by bomb threats on Thursday morning.

Flight FR1730 left the airport at 6am and was scheduled to land in the capital Sofia at 9.25am GMT, but was diverted to Plovdiv, according to Flightradar24.

Heathrow and Birmingham airports also both received threats, which were assessed as not credible.

It is understood that operations at both UK airports have continued as normal.

As of 2pm, at least eighteen flights across Europe had been affected by bomb alerts.

Many of the threatened planes have been inspected upon landing, with no explosives or suspicious items found on board.

The Bulgarian air force confirmed that it successfully carried out an "air policing" mission following threats to three flights into the country.

The Ryanair flights to Sofia, which flew out of Copenhagen, Madrid and London, were intercepted by MiG-29 fighter jets which then intercepted and escort the aircrafts.

A Wizz Air spokesperson said its flight from Milan to Warsaw was diverted to Vienna after a bomb threat was received during the flight.

They added: "The diversion was initiated in accordance with established security protocols and procedures, with the safety of passengers and crew as the highest priority.”

Meanwhile, Italian authorities said that threats against two inbound flights this morning came by email, signed on behalf of the supposed "Fighters of the Male State".

The group claimed to be targeting a "feminist regime" and threatened to "turn the skies red" with explosions.

Czech police said that four as-yet unidentified flights also received threats, with no explosives found upon landing.

The bomb alerts come two days after multiple flights, including one from Heathrow and another from Manchester, were subject to bomb alerts.

The Government said the two UK flights were targeted in “malicious hoax threats”.

Flig.ht LO286 from Heathrow landed at Warsaw Modlin Airport just seven minutes after the alarm was raised.

The airport was closed as security operations got underway.

On Monday, a Wizz Air flight from London Luton made an emergency landing in Budapest, escorted by a Hungarian fighter jet, following a bomb threat.

Asked about the threats, transport secretary Heidi Alexander told reporters: "I am aware a small number of flights across Europe have been disrupted.

"We do have some of the most robust aviation security systems of anywhere in the world, and we have established processes for dealing with hoax and malicious threats, and that's what these threats have been."