LONDON (Reuters) - A British frigate escorted Russian ships through the English Channel on Monday, Britain’s defense ministry said, adding that it was the latest sign of an upsurge in Russian naval activity near UK waters over the festive period.

Royal Navy frigate HMS Westminster was sent to monitor four Russian vessels over the weekend as they passed close to British waters, the Ministry of Defence (MoD) said, and will stay with the warships as they head north.

The MoD added that two Russian frigates, Soobrazitelny and Boiky, and support vessels, Paradoks and Kola, were believed to be returning from operations in the Middle East.

“The English Channel is an absolute lifeline for the UK, and it is very important HMS Westminster and the Royal Navy maintains a watchful eye on this key strategic link,” Simon Kelly, Commanding Officer of HMS Westminster, said in a statement.

Britain said that the number of such incidents had increased in recent weeks.

Over Christmas, a British ship escorted new Russian warship Admiral Gorshkov as it passed near UK territorial waters, which Britain said was one of a four of vessels monitored during that period.