Russian tanks pounded Chechen positions near the western village of Bamut yesterday as its forces consolidated a security zone carved out in the north of the breakaway republic, reports said.
Federal army tanks launched an early-morning barrage on the outskirts of Bamut for about 40 minutes from the neighbouring Russian republic of Ingushetia, ITAR-TASS news agency said, citing the Ingush interior ministry.
Chechen oil-refining facilities were thought to be the targets, television news reports said, but Russian officials maintained media silence.
Local officials in the southern Russian region of Stavropol said the North Caucasus army group had penetrated up to 5km into Chechen territory in the districts of Naursky and Shelkovsky.
Government troops had secured the high ground and were reinforcing positions to guard against a counterattack by Chechen forces, ITAR-TASS said, quoting the press service of the local administration.
Meanwhile, Chechen officials said air strikes by the Russian air force since September 5th have killed 600 Chechen civilians and caused a massive refugee exodus to neighbouring Russian republics.
President Ruslan Aushev of Ingushetia said yesterday that some 110,000 Chechens had fled west to his republic, warning that the humanitarian situation in the southern Russian republic was becoming "dire".
In the Chechen capital, Grozny, officials said that 64 Russian and three Chechen soldiers have been killed in fighting in northern Chechnya in the past 24 hours.
There was no Russian confirmation of the report, and Moscow has denied Chechen claims that 10 Russians were killed on Friday during the first ground force clashes in the breakaway republic.
Russian news agencies said that federal troops destroyed a column of 18 Chechen military vehicles on Saturday night and killed 30 Chechen fighters, but there was no comment on this from Grozny.
Gen Valery Manilov, Russia's First Deputy Chief-of-Staff, said on Saturday that Russian troops had advanced into Chechnya on three fronts, as part of an operation to cut off Chechnya from the rest of the federation.
Russia says its military operation aims to smash terrorist bases in Chechnya, and is not a repeat of the disastrous 1994-96 war in which 80,000 people, mainly civilians, died.
In Moscow, President Boris Yeltsin made a rare Sunday appearance at the Kremlin for a series of working meetings, a Kremlin spokesman said without giving further detail.
In Berlin, the German Foreign Minister, Mr Joschka Fischer, urged his Russian counterpart, Mr Igor Ivanov, to open talks to end the violence in Chechnya, said a German Foreign Ministry statement. In a telephone conversation, Mr Fischer expressed Germany's "deep concern" about the continuing air and artillery attacks on Chechnya.
The European Union has signalled it is ready to play a lead role in Western efforts to prevent another war in Russia's Chechnya region, posing a difficult challenge for its new leadership.
EU sources had said last Monday that the 15-nation bloc would not resort to "megaphone diplomacy" over Russia's bombing campaign against Chechnya. By Friday the megaphone had been turned up to full volume.
The Chechnya crisis means an early challenge for Mr Chris Patten who, as the EU's new Commissioner for Foreign Relations, is due to visit Moscow late next week and could end up, at least briefly, playing the role of the West's emissary.
"Patten has a very delicate role, but a very important one, in reassuring the Russians they can expect solidarity in the face of terrorism but encouraging them to show great caution in handling Chechnya," said a political analyst, Mr John Palmer.
"The West is facing awkward questions about what its responsibilities are as a world community in such situations," said Mr Palmer, head of the European Policy Centre think-tank.