The Russian security service has published photographs which it says prove a key suspect in the deadly 1999 apartment blasts had ties with a Chechen warlord, whom Moscow blames for organising the bombings.

Russia began second Chechen war within weeks after the blasts

The security service (FSB) said the pictures showed the suspect, Achimez Gochiyayev, and Chechen leader Khattab, who was killed earlier this year.

The FSB claims that Mr Gochiyayev received $500,000 from Khattab to carry out the attacks.

The blasts in September 1999 - two in Moscow and two in Volgodonsk - killed nearly 300 people and prompted Russia to sent its troops to Chechnya.

The pictures appeared a day after a dissident FSB agent, Alexander Litvinenko, presented evidence which he said proved Mr Gochiyayev's innocence.

He claimed instead that the FSB was behind the blasts.

Opposing theories

The FSB said it decided to publish the photos because of high level of public interest following the allegations by the former FSB agent.

On Thursday, Mr Litvinenko told an unofficial commission by video link from London to Moscow, that he had a handwritten statement from Mr Gochiyayev denying his ties with Khattab.

Litvinenko (on the screen) fled to Britain in 2000

In addition, Mr Litvinenko said a British forensic analyst said it could not be determined whether the man in the photo was in fact Mr Gochiyayev.

The analyst, Geoffrey Oxlee, confirmed that statement.

Mr Litvinenko also said Mr Gochiyayev's statement proved that the FSB organised the blasts as a pretext to start the second Chechen war.

He said Mr Gochiyayev wrote that he had rented rooms in the Moscow buildings where two of the explosions took place, at the request of an old friend, whom he now believed was an FSB agent.

The FSB dismissed Mr Litvinenko's evidence, saying it did not want to be a part of his "show".

It produced a video recording of its own interrogation of another suspect, saying that it proved that Chechen rebels were responsible for the blasts in September 1999.

Russia's leading networks showed the FSB footage where the suspect - Adam Dekkushev - apparently explained how explosives were brought to Moscow.

'Troubled relationship'

Mr Litvinenko's troubles with the FSB began in 1998 after he told the Russian media about an alleged plot by his superiors to assassinate a controversial Russian oligarch Boris Berezovsky.

Litvinenko accused the FSB of plotting to kill Berezovsky

Mr Litvinenko also wrote a book accusing his former bosses at the FSB of carrying out the Moscow apartment bombings.

He was arrested in 1999 and spent nine months in jail on charges of abuse of office.

He later was acquitted of all charges and fled to London, where he was given political asylum.

Last month Mr Litvinenko was tried in absentia by a Russian court and convicted to a three-and-a-half-year suspended prison sentence for abuse of office and stealing explosives.