The Russian A321 Airbus, registered to Aeroflot as flight SU2582, was searched by UK authorities after flying from Sheremetyevo in Moscow to London.
Officers boarded the flight “without grounds” shortly after it touched down at London Heathrow airport at 3.37pm local time on Friday.
Shortly after landing, police “insistently” asked passengers and crew to leave, but the pilots refused, according to multiple reports coming from Russia.
“After the passengers left the aircraft, policemen insistently demanded the crew to leave the plane in order to conduct an inspection there in the absence of the crew,” a source told Russian news agency Interfax.
Scotland Yard has denied its officers are carrying out a search of the plane, but an Aeroflot source has confirmed a plane is being searched at Heathrow, Tom Parfitt, Moscow correspondent for The Times, tweeted.
Representatives from the Russian Embassy are reportedly being sent to the scene.
Parfitt wrote: “Aeroflot confirms it has plane being inspected at Heathrow. Russian embassy in London says it is sending representatives to the scene. Russian foreign ministry says it is ‘inadmissible, dangerous irresponsible’ and could be ‘provocation’ by UK to save reputation over Skripal affair.”
British police “did not explain the reasons” why they were searching the plane and the crew, the source told Interfax.
They insisted on inspecting the “entire crew”, the source added.
Piers Scholfield, foreign news producer for the BBC, tweeted: “FCO has said ‘customs officers boarded a plane in London’.”
BBC journalist Ben Tavener added: “UK #Russia plane search: UK Foreign Office confirms to the BBC that it was Customs inspecting the Aeroflot flight at Heathrow this afternoon. The airline says it is willing to cooperate with UK authorities if explanation given.”
Maria Zakharova, a spokeswoman for the Russian Foreign Ministry, said: “The British authorities asked the Russian crew, including the captain, to leave the plane.
“The commander of the aircraft proposed the inspection to be conducted in his presence as he’s forbidden from leaving the plane in accordance with the regulations.
“At the moment, the police proceed with the search without releasing the commander from the cabin and preventing him from being present during the inspection.