LONDON, December 7 (RIA Novosti) - Russian security service defector Alexander Litvinenko, killed by poisoning in London last month, was laid to rest in a London cemetery Thursday.

Four cars with tinted windows drove to north London's Highgate Cemetery, cordoned off by police, at about 1 p.m. GMT, with several dozen reporters already waiting at the gates.

Relatives and friends, including Chechen militant Ahmed Zakayev, wanted in Russia for terrorism, came to pay their last respects to Litvinenko, a British national who according to his father converted to Islam soon before his death.

Litvinenko, an outspoken critic of President Vladimir Putin's administration and a close associate of exiled Russian oligarch Boris Berezovsky, died in a London hospital on November 23. His body was found to contain a lethal dose of polonium-210, a radioactive isotope.

The murder of Litvinenko is being investigated in Russia by Scotland Yard detectives, who arrived in Moscow on Monday.

Highgate Cemetery is a famous graveyard opened in 1839 as one of seven large cemeteries, known as Magnificent Seven, around London. The cemetery is the final resting place for many historical figures, among them German philosopher and revolutionary Karl Marx, novelist George Elliot, and scientist Michael Faraday.

Western media reported earlier that Litvinenko's body would have to be sealed in an airtight container due to radioactivity risks, and that it cannot be cremated for 22 years.