A Russian frigate Yaroslav Mudry sailed through the English Channel on Friday — where it was closely followed by the Royal Navy in another sign of heightened tensions between the two countries.

The 423-foot Russian ship cruised close to the English coastline and past the Dover Straight while the HMS St Albans, the Royal Navy’s “very high readiness ship” that is charged with coastal defense, kept a wary eye on it, according to a report in the UK’s Sun newspaper.

The UK’s vessel is equipped with a Merlin helicopter from Culdrose-based 829 Naval Air Squadron and state-of-the-art radar, the paper reported.

“As the Royal Navy’s high readiness unit in UK waters, we are the first responders to any potential incursion into UK waters and are highly trained in this role,” said Commander John Cromie, the commanding officer of the St Albans.

“Our activation today in response to the passage of a Russian warship close to the UK resulted in a cordial interaction between professional sailors based on the recognized conventions at sea,” he continued.

“We are always standing ready, as is the rest of the fleet, to defend UK waters and UK sovereignty 24 hours a day, 365 days a year.”

The encounter came after Downing Street blamed the Kremlin for poisoning former spy Sergei Skripal and his daughter with the Soviet-era nerve agent Novichok earlier this month.

The US, Britain and France’s coordinated attack on Syria also irritated Vladimir Putin, who is trying to prop up fellow strongman Bashar al-Assad’s regime in the war-torn country’s civil war.