Alexander Litvinenko's widow said his criticism of the Kremlin had antagonized his former secret service colleagues, and contended that Russian President Vladimir Putin had created an atmosphere that "makes it possible to kill a British person on British soil."

In her first interviews, published Sunday, Marina Litvinenko said she believed Russian authorities were behind the poisoning of her husband, who sought asylum in Britain in 2000 and obtained citizenship this year. British police are treating it as a murder.

Marina Litvinenko told Sky News in an English-language interview that her husband "openly went out from system and accused the system of killing people, of kidnap."

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"System never forgive you about this," she said.

Also on Sunday, a friend of Litvinenko accused Russian authorities of hampering the British probe into the poisoning death of the former KGB agent by preventing two key witnesses from being questioned and he warned the pair could be in danger.

In interviews with two Sunday newspapers and a British broadcaster, Marina Litvinenko recalled the days leading up to the Nov. 23 death of her 43-year-old husband from poisoning with polonium-210, a rare radioactive substance.

"Marina, I love you so much," Litvinenko told his wife in the last hours of his life. She said they were his last words.

Litvinenko fell ill on Nov. 1, a day the couple always celebrated because it was the anniversary of their arrival in Britain.

She said he vomited repeatedly and told her "everything was strange, looked gray. He said, 'It looks like someone has poisoned me. When I was in military school, I learned about this."'

Every time she went to the hospital to see her husband, she could see the toll the poison was taking on his once-healthy body, telling the Sunday Times "each day for him was like 10 years — he became older in how he looked."

Click here to read the Sunday Times interview.

Litvinenko himself believed he had been targeted, and he and his emigre allies have blamed Putin for the poisoning — allegations that have been strongly denied.

"Obviously it was not Putin himself, of course not," Marina Litvinenko told the Mail on Sunday. "But what Putin does around him in Russia makes it possible to kill a British person on British soil. I believe that it could have been the Russian authorities."

Marina Litvinenko has placed her faith in British investigators. She said she does not intend to cooperate with Russian authorities, who plan to come to London to probe her husband's death.

"In Russia, it doesn't matter how many people are killed," she said, adding that the life of "only one person can still be very important in England."

Litvinenko's friend Alex Goldfarb accused Russian authorities of trying to obstruct the British probe by preventing key witnesses Andrei Lugovoi and Dmitry Kovtun from being questioned.

Lugovoi, who met with Litvinenko in a London hotel on the day he believed he was poisoned, was supposed to testify after a team of Scotland Yard officers arrived in Moscow on Tuesday. But the interrogation has been postponed several times, although Lugovoi himself has said he is eager to answer questions.

Kovtun, a business associate of Lugovoi, also met with Litvinenko at the hotel. He is reportedly being treated in Moscow for symptoms of radiation poisoning.

"It's a clumsy effort to cover up the trace, to prevent British investigators from meeting with two key witnesses," Goldfarb told The Associated Press.

He added that Lugovoi and Kovtun could be in danger as the authorities "could try to remove them later."

"Another crime is unfolding before our eyes — the removal of two key witnesses: Lugovoi and Kovtun," he told the AP.

Lugovoi, who is being checked in Russia for radioactive poisoning, said Sunday his condition was "stable" and results of his medical checks would be available by the end of the week.

Lugovoi said Kovtun also was in a "satisfactory" condition. "He's not in a coma," Lugovoi told the RIA Novosti, denying a report by the Interfax news agency on Thursday.

Goldfarb also claimed that Vyacheslav Sokolenko, an associate of Lugovoi and Kovtun, could have played the main role in Litvinenko's death.

Sokolenko on Sunday dismissed the allegations of his involvement as "ravings." He told the AP that he was at the London hotel but did not participate in the Russian gathering there.

Russian prosecutors have filed a criminal case for the murder of Litvinenko and attempted murder of Kovtun, and the chief prosecutor's office said it was going to send investigators to London.

The move to open a criminal probe in Russia would allow suspects to be prosecuted in Russia. Officials previously have said that Russia would not extradite any suspects in Litvinenko's killing.

In Germany, authorities said Sunday they have found traces polonium-210 at an apartment visited by Kovtun before they met in London and were investigating Kovtun on suspicion of improper handling of radioactive material.

Investigators said the Russian businessman visited his ex-wife's Hamburg apartment the night before heading to London, where he met Litvinenko. Radiation was found on a couch in his ex-wife's apartment, on a document he brought to Hamburg immigration authorities and in the passenger seat of the BMW car that picked him up from Hamburg airport, police said.

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