The Nobel prize winning Medecins Sans Frontieres (MSF) has appealed to US President Bill Clinton to step up pressure on Moscow to change its behaviour.

Amnesty International and Human Rights Watch (HRW) also supported the French aid organisation.

The criticism came as Russia reported that towns lost to the Chechen rebels at the weekend were being recaptured.

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The Russian army says it is continuing to push further into the Chechen mountains and that paratroopers had taken control of a strategic mountain road, cutting off a rebel supply route.

But the fighting does not appear to be going all Moscow's way - the Interfax news agency, quoting federal military sources, reported on Friday that 33 Russian soldiers had been killed and 26 injured in the previous 24 hours.

HRW accuses Moscow of deliberately flouting its international obligations and Amnesty has called on both sides in the conflict to allow civilians to leave the Chechen capital, Grozny.

Amnesty said those people left in Grozny were running out of supplies.

It is unclear how many civilians are trapped in Grozny. Russian authorities have said about 20,000 people are still in the devastated city, but Chechen fighters say the number is closer to 40,000.

Passport controls

Federal troops combed Russian-controlled areas of Chechnya on Thursday looking for hidden rebels, checking residents' papers in the towns of Argun and Shali, east and southeast of Grozny.

A Russian spokesman said 13 people were detained on suspicion of militant activity.

Russian Interior Minister Vladimir Rushailo restated Moscow's determination to deal harshly with Chechen rebels during a visit to the territory.

In the village of Avtury, he said: "There are only two ways to cope with the bandits - either to liquidate them or to put them in the dock. This is what we are now doing".

He said the tight controls announced earlier in the week would be maintained.

Meanwhile, Russian Defence Minister Igor Sergeyev pledged to continue the campaign to capture Grozny, as fierce street battles continued in central parts of the city.

He was also quoted as saying that in one town, Urus-Martan, Russian soldiers had found tonnes of explosives similar to those which killed about 300 people in attacks on Russian apartment blocks last year.

At the weekend Russia suffered its worst setback of the four-month campaign with devastating rebel counter-attacks inflicting heavy losses and humiliation on Russia's military command.

US influence

In Washington, the visiting Chechen foreign minister Iliyas Ahmadov said he would welcome help from the Clinton administration in ending the conflict.

He said: "We are not calling on the United States to become a guarantor or a mediator in this case, but if they actually express this wish to become one we would only welcome it.

"The United States has tremendous influence in Europe as well as elsewhere. It can influence the situation."

The US has so far ruled out such a role but State Department spokesman James Rubin said: "We don't believe that the result of force is going to be the melting away of resistance.

"We believe that the Russians are in a cul-de-sac."

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