The United States has called on Moscow to tell the truth about the fate of a missing Russian journalist who worked for the American-funded Radio Liberty in Chechnya.

Washington has expressed scepticism about Russia's claims that Russian forces handed over the journalist, Andrei Babitsky, to Chechen rebels last week in exchange for prisoners of war.

A spokesman for the US State Department, James Rubin, said the authorities in Moscow were responsible for the well-being and safety of Mr Babitsky, whose reporting has angered the Russian authorities.

Russian Interior Minister Vladimir Rushailo said on Tuesday that Mr Babitsky was alive and well.

Washington expresses fears

But Mr Rubin said the reporter's disappearance, and incomplete and contradictory explanations by Russian officials, had "raised the greatest fears as to his fate".

US Secretary of State, Madeleine Albright, also said Washington had made its concern over the journalist's fate known in Moscow.

A group of 21 members of the US Congress have also written to acting Russian President Vladimir Putin urging him to secure Mr Babitsky's release.

The letter said that the idea that Mr Babitsky had been swapped for Russian soldiers was incomprehensible.

It added that the claim appeared to be an attempt to suggest that the journalist was affiliated with the rebels when, in fact, his reporting had been objective and fair.

Confusion over exchange

Mr Babitsky, one of the leading war reporters in Russia, had been covering the Chechen conflict from rebel-held areas, including Grozny.

During his attempt to leave the besieged city last month he was seized by Russian troops and accused of being part of a rebel group, which he denies.

After days of detention in Chechnya, Russian officials said Mr Babitsky was formally freed but had volunteered to be swapped for Russian prisoners of war held by one of the Chechen groups.

But the rebels later denied any of their commanders were involved in any such swap.

On Tuesday, Russian TV showed a video which appeared to show Mr Babitsky after the exchange.

However, the journalist's colleagues at Radio Liberty's Moscow bureau have said it is impossible to verify when the footage was filmed or where and by who Mr Babitsky was being held.

According to their sources, Mr Babitsky was last seen on Monday - the day after the message was apparently taped - in Gudermes, Chechnya's second city which is under Russian control.

The journalist had been severely beaten, according to the source.

Mystery of the Chechen spokesman

The mystery deepened on Wednesday after Ilya Akhmadov, a spokesman for Chechen President Aslan Maskhadov, denied that Mr Babitsky was being held by the rebels.

The statement contradicted a previous statement by a man in Moscow called Sharip Yussupov who said he was a Chechen spokesman and that Mr Babitsky was being held by the guerillas.

But Mr Akhmadov told Moscow's Radio Echo: "I categorically and officially deny everything Yussupov has said, and I deny that he is a spokesman for Maskhadov.

"We don't have representatives in Moscow, nor a single person who can speak in the name of Chechnya's official structures."