British police are investigating a claim by a former Soviet spy that he was poisoned with tainted pills in an assassination attempt by rogue elements in Moscow.

Oleg Gordievsky, a double agent who defected to Britain after his cover was blown in 1985, said Monday that he became sick after taking the pills at his home in southern England on Oct. 31.

He told The Associated Press that a London-based Russian business associate had supplied him with pills, which he said were the sedative Xanax, after Gordievsky complained of insomnia.

Gordievsky said the suspect pills were bigger than the other tablets, and white instead of gray, but that he had been assured by the associate's wife that they were safe.

He refused to identify the associate, saying British authorities had advised against it.

Gordievsky, 69, said he was taken from his home south of London to a local hospital by ambulance on Nov. 2 and spent 34 hours unconscious.

"I've known for some time that I am on the assassination list drawn up by rogue elements in Moscow," Gordievsky told the Mail on Sunday newspaper. "It was obvious to me I had been poisoned."

Surrey Police confirmed officers were called to Gordievsky's house on Nov. 2 "following concerns for the safety of a man" aged 69.

Surrey Police are "continuing to investigate allegations made by this man and it would not be appropriate to comment further until our investigation is complete," the force said in a statement.

Gordievsky claimed police had initially been slow to investigate, and alleged British authorities were downplaying the incident because they wished to avoid a further deterioration of relations with Russia.

Relations between London and Moscow have been tense since the death of Alexander Litvinenko, a former KGB officer killed by radioactive poisoning in London in 2006. Russia refuses to extradite the man identified by British police as the prime suspect.

Only after a series of strongly worded letters complaining that too little was being done did British authorities assign a special forensic team from MI5, the domestic intelligence service, to the case, Gordievsky said.

"I am the victim of international politics," Gordievsky said.

Police would not confirm or deny the presence of MI5 investigators on the case.

British intelligence recruited Gordievsky in the 1960s and he later became invaluable when Moscow assigned him to its London Embassy to spy on Britain in 1982. Three years later, his cover was blown and he was arrested while in the Soviet Union. He was released due to a lack of evidence and escaped by secretly boarding a train to Finland — the most senior Soviet spy to defect to the West during the Cold War.

Last year, Gordievsky was given one of Britain's highest honors when Queen Elizabeth II named him a Companion to the Order of St. Michael and St. George, or CMG. The honor, for individuals who have rendered services related to Commonwealth or foreign nations, is the same accolade held by the fictional British spy James Bond.