MOSCOW, March 30. /TASS/. Russia’s Aeroflot plane has been searched by the British authorities at London’s Heathrow airport, no reasons were given, an Aeroflot source told TASS on Friday.

"The British side provided no grounds for a plane search," the source said. "It was decided that after the British side finishes the search, the plane will be additionally examined by the crew and the company’s office employees as the British side compelled the crew to leave the plane during the search."

Russia’s relations with the United Kingdom strained following the incident involving the alleged poisoning of former Russian military intelligence officer Sergei Skripal who had been convicted in Russia of spying for Great Britain and was later swapped for Russian intelligence officers.

On March 4, Skripal, 66, and his daughter Yulia, 33, were found unconscious on a bench near the Maltings shopping center in Salisbury, the UK. Police said they had allegedly been exposed to a nerve agent. Both are in the hospital in critical condition.

London immediately accused Russia of being involved, but failed to produce any evidence. UK Prime Minister Theresa May rushed to blame Russia for "unlawful use of force" against her country. She identified the alleged substance used in the attack as the so-called Novichok nerve agent, allegedly developed in the former Soviet Union. The UK expelled 23 Russian diplomats and announced other restrictive measures against Moscow.

Russia has flatly rejected these allegations pointing out that neither the Soviet Union nor Russia had any programs to develop that substance. In response, Moscow expelled the same number of British diplomats from Russia and ordering to close the British Consulate-General in St. Petersburg and shut down the British Council’s offices in Russia.