The troop movements came as Russian warplanes and artillery continued to pound Chechen villages along the Dagestani border on Saturday night, the Chechen interior ministry information service in Grozny said.

The troops are in the process of sealing the border with the breakaway Russian Republic of Chechnya, NTV television reported. They are taking up positions in the neighbouring territories of Ingushetia, North Ossetia and the southern Russian region of Stavropol. Two Russian batallions arrived in Ingushetia Saturday and were joined by a third early Sunday, NTV said.

Russian Prime Minister Vladimir Putin discussed sealing the Chechen border on Friday during a closed-door parliamentary session, NTV said on Sunday.Non-official sources said troops were preparing for a large-scaleoperation against Islamic rebels based in Chechnya who have invaded Dagestan twice in recent months. Russian motorised units crossed above into Chechnya on Saturday, the Chechen Chief of staff in Grozny told Interfax News Agency.

The Russian defence ministry in Moscow did not confirm that ground troops were involved, but if true, it would be the first time Russian troops have entered Chechnya since the end of the Russo-Chechen War in 1996.

Russia did confirm on Saturday it had been bombing what it described as Islamist bases to prevent another attack on the republic of Dagestan, ITAR-TASS reported.

Some 140 Islamic rebels based in Chechnya have been killed in the past 24 hours amid heavy bombardment by Russian forces, Interfax reported on Sunday, citing a Russian army spokesman in the Dagestani capital Makhachkala.It was the first time Russian military authorities had announced losses among the insurgents caused by attacks on Chechnya. Chechen authorities have charged the attacks have killed more than200 civilians since September 5. An AFP correspondent in the Chechen village of Ishkok-Yurt reported on Saturday that some 200 houses had been destroyed or damaged there.

Moscow, however, has denied targeting civilians and insisted it has only bombarded concentrations of rebel troops and bases.

A ground invasion by Russian troops would represent a serious escalation of events since Islamic guerrillas started a new rebellion in neighbouring Dagestan in August, analysts said. A wave of terrorist bombings that has claimed 292 lives and been blamed on Islamic militants seems to have cemented Moscow's resolve to quash the rebellion.

The insurgency started on August 7, when rebels from Chechnya seized villages in Dagestan as part of a drive to recreate a 19th century Islamic state encompassing the two southern Russian republics.