MOSCOW (AP) -- Two exiled Kremlin adversaries refused to answer key questions posed by Russian authorities probing the poisoning death of a former KGB agent, a Russian investigator said in an interview published Monday.

Tycoon Boris Berezovsky and Chechen rebel envoy Akhmed Zakayev answered fewer than half the questions they were asked in London late last month, the head of the team of Russian investigators, Andrei Mayorov, told the official newspaper Rossiyskaya Gazeta.

"In a word, they did not answer the most key questions," Mayorov said.

Alexander Litvinenko, a Kremlin critic and Berezovsky associate, died in a London hospital in November following a dose of radioactive polonium-210.

Mayorov made no accusations against Berezovsky and Zakayev, referring to them as witnesses. But he told Rossiyskaya Gazeta that Berezovsky declined to answer questions about his financial and business ties to Litvinenko, adding that "Litvinenko, especially recently, in many ways depended on (Berezovsky)."

Russian media have speculated that a falling-out between Berezovsky and Litvinenko over money could have led to the former spy's death. Russia's chief prosecutor also has said it was possible Russians living abroad could have killed Litvinenko, and pro-Kremlin lawmakers and state-controlled media have said Berezovsky could have been behind his death.

In a telephone interview with The Associated Press in London, Berezovsky said Monday that investigators had asked him some 200 questions during the meeting and he refused to answer about 20 of them that focused on his private business dealings and the whereabouts of a Russian journalist who had been critical of Putin and the Kremlin.

He said the questioning had been taped and he planned to get a transcript of the interview in both Russian and English.

In an earlier interview with the AP, Berezovsky said he told Russian authorities during the meeting that he had nothing to hide and repeated his allegation that the Kremlin was behind Litvinenko's death. He also said many of the questions were about his finances, not the poisoning case.

"It was ridiculous. I spent four hours at a police station and they asked me about my bank accounts," Berezovsky said.

Zakayev did not immediately return two messages seeking comment Monday.

Mayorov said Berezovsky refused to talk about how Litvinenko had been making a living or about people Russian investigators believe met with Litvinenko shortly before his poisoning.

"All this important information, which doubtless would help the investigation, we could have received from Berezovsky and Zakayev, who called themselves the deceased's best friends. But they said nothing," said Mayorov.

Later in the interview, he suggested financial ties between Litvinenko and Berezovsky could have led to the poisoning, saying that some of the theories about the case are interconnected.

"This is precisely why Berezovsky was asked questions about his financial dealings with Litvinenko," he said.

British authorities have said they conducted the interviews on behalf of Russian investigators — the same format as when British investigators visited Moscow in December as part of their probe.

Among those questioned by British authorities were Andrei Lugovoi and Dmitry Kovtun, two Russians with military and security backgrounds who met with Litvinenko in London the day he said he fell ill. British authorities have filed no charges. ___