"I have today concluded that the evidence sent to us by the police is sufficient to charge Andrei Lugovoi with the murder of Mr. Litvinenko by deliberate poisoning," Director of Public Prosecutions Ken Macdonald said.
Litvinenko, 43, died from polonium-210 poisoning in a London hospital Nov. 23, and on his deathbed accused President Vladimir Putin of being behind his killing. The Russian government denies involvement.
Within hours of the charge being announced in London, the Russian prosecutor-general's office said it would not turn over Lugovoi, the Interfax news agency reported.
"In accordance with Russian law, citizens of Russia cannot be turned over to foreign states," the agency quoted prosecutor's office spokeswoman Marina Gridneva as saying.
The office declined comment to The Associated Press, referring callers to Russian agency reports.
Lugovoi and a business associate, Dimitri Kovtun, met with the former spy at London's Millennium Hotel on the morning he fell ill. The hotel is among a number of sites where investigators found traces of Polonium 210 — the radioactive isotope responsible for killing Litvinenko.
Lugovoi, a former KGB agent who now runs a private security firm, was also contaminated by radioactive polonium, but has always insisted - including during an interview with CBS News - that he was the target of a set-up and not the perpetrator of a crime, reports CBS News correspondent Richard Roth.
He reiterated his innocence Tuesday.
"I consider that this decision to be political, I did not kill Litvinenko, I have no relation to his death and I can only express well-founded distrust for the so-called basis of proof collected by British judicial officials," Lugovoi was quoted as saying by RIA-Novosti and other agencies as saying.
Many legal observers in Britain had expected the Crown Prosecution Service to announce charges against both Lugovoi and Kovtun, but the CPS statement read by Macdonald on Tuesday gave no indication of any further charges or suspects in the case.
Litvinenko's widow, Marina, said Tuesday that she hoped justice was done in the case. Speaking through her lawyer, Louise Christian, she said she had thanked British police for their efforts leading to the charge, but hoped Lugovoi would be extradited to Britain.
"She thanks the police, but is anxious that justice is done," Christian told The Associated Press by telephone.
The politically charged case has driven relations between London and Moscow to post-Cold War lows. The Russian Prosecutor General's office has long said Moscow would not extradite suspects to Britain if charges were filed against Russians.
However, a Russian lawmaker raised doubts about the claim that Russian law prevented such extraditions.
Yuri Sharandin, chairman of the constitutional legislation committee of the Federation Council, the upper house of parliament, said it was possible for Russia to extradite its citizens, but that it also could refuse such requests.
Sharandin said on Ekho Moskvy radio that the matter would come under the European Convention on Extradition, to which both Russia and Britain are signatories.
He said the convention allows for such extraditions, but also gives the country receiving the request the right to refuse.
British Foreign Secretary Margaret Beckett told the Russian ambassador in London that her government expected "full cooperation" from Moscow in getting Lugovoi extradited.
Litvinenko was a vocal Kremlin critic who accused Russian authorities of being behind deadly 1999 apartment building bombings that stoked support for a renewed offensive against separatists in Chechnya.
Police in London and Moscow have launched parallel investigations, but so far no one has been arrested.