Russian warships have been tracked by the Navy through UK waters in an “intense” 72-hour operation.

A task group was shadowed by Type 45 destroyer HMS Duncan, Type 23 frigate HMS St Albans and patrol vessel HMS Severn as it made its way from the North Sea through the English Channel.

Russian destroyer Admiral Levchenko was watched escorting sanctioned cargo vessels General Skobelev and Sparta, with a Merlin helicopter extending the UK’s surveillance as the ships approached the Strait of Dover.

In response to the tracking, Russia deployed other military resources including the Neustrashimy frigate to guard the illegal shipment, UK officials said.

First Sea Lord General Sir Gwyn Jenkins said there was “no room for complacency” as shadow fleet vessels continue to pose “an unacceptable risk” to maritime security and the environment.

“Alongside our allies, this approach is forcing Moscow to divert Russian warships away from their core purpose. That is because Russia knows we stand ready to act again, should it be required,” he said.

The Navy vessels handed over monitoring duties to a Nato ally off the coast of France near Ushant following the “intense” 72-hour operation last week, officials said.

Earlier this month, the Navy warned of increasing Russian activity around the UK’s waters after it spent 21 days in July monitoring Moscow’s ships.

Naval operations to monitor Russian activity increased 25% in July compared to the previous year, with warships making repeated voyages through the Dover Strait and North Sea.

Moscow uses its shadow fleet of ageing vessels to evade international sanctions on its oil and fund the war in Ukraine.

The increase in Russian naval activity follows the seizure of the tanker Smyrtos by Royal Marines in June, the first time British troops have directly boarded a shadow fleet vessel.

It comes after a week of repeated threats from the Kremlin to the UK following Andy Burnham’s visit to Kyiv, during which he announced Britain would provide Ukraine with blueprints for long-range Scalp missiles.

Western officials have sought to play down the prospect of a conflict between Russia and Nato, despite senior figures in Moscow accusing Ukraine’s allies, including the UK, of “playing with fire”.

Ex-Russian foreign minister Andrei Fedorov also said he could not “100% exclude” the possibility of “semi-military” action against Britain in retaliation, raising the prospect of an attack on British drone factories from “unknown sources.”

On Friday, Western officials said the threats were “not a new phenomenon” but part of “long-standing Russian military doctrine” that seeks to use “hostile rhetoric” to “exploit fears” and influence decisions.

“We do need to be careful to distinguish what is real from what is rhetoric designed to scare and deter us. Replaying Russian threats and heightening a sense of crisis is exactly what the Kremlin wants,” they said.

“Our assessment remains that Russia isn’t seeking direct confrontation with Nato.”