Chechen rebels ambushed a Russian military column yesterday while Moscow said that clashes have also resumed in the rebel capital, Grozny, which is now under nominal federal control.
The latest attack came at the entrance of the Argun Gorge near the foot of the republic's southern mountains in which the majority of an estimated rebel force of 3,000 is now based.
Gen. Valery Manilov said the battle, involving a paratrooper division based in the central Tula region, lasted for just over an hour and only one Russian soldier had been hurt.
However, NTV private television reported from Chechnya that fighting, which involved Russian jets and helicopters, had raged for about five hours after the initial attack.
The raid came three days after Moscow admitted that a Chechen ambush of a Russian supply column left at least 13 soldiers dead. The rebels claim to have killed 80 Russians in Sunday's attack.
Adding to a new sense of urgency in the nearly seven-month war, Russian sources said that 500 well-armed Chechen fighters were in Grozny and were preparing their own counterattack.
"We are seeing an increase in the number of bandits in Grozny," Gen. Manilov conceded. "Many are hiding like rats in underground communication routes." Limited to rapid night-time raids in the past, Grozny's sniper attacks have now spilled over into daytime, Moscow reports said.
On Sunday Russian forces said the entire city had been cleared of mines and Grozny was now ready for the return of civilians who had fled the devastated capital.
Grozny fell to government forces in February after a four-month Russian air and artillery assault. An estimated 1,500-strong Chechen force then attempted to evacuate the city overnight, although many were killed when they stumbled across Russian mine fields.
The rebels have since regrouped in the republic's mountains where they are using the cover of the spring bloom to open a guerrilla counterattack aimed primarily against government supply columns.
Chechen fighters used similar tactics in their victorious 19941996 conflict that saw Moscow sue for peace and leave the republic with de facto independence.
Russian forces returned last year after Chechens staged two incursions into neighbouring Dagestan and were held responsible for a series of Russian bomb blasts that killed almost 300 people.
The President-elect, Mr Vladimir Putin, whose election last month was helped by the popular war, has vowed that government troops will never again leave Chechnya until they have secured full control over the republic.
An offer of talks by the separatist President, Mr Aslan Maskhadov, whose rule is no longer recognised as legitimate by Moscow, was again brushed aside by Russia yesterday despite strong Western pressure for negotiations.
"In order to hold talks with Maskhadov, he first must fulfil a whole list of conditions," the Interior Minister, Mr Vladimir Rushailo, told NTV television from the southern Russian city of Vladikavkaz.
"This includes the hand-over of rebel leaders, the immediate release of all hostages being held in Chechnya, and a whole range of other conditions," he said. "As far as we understand, he cannot meet these conditions at this time, so the question of holding talks with him is simply irrelevant."
Gen. Manilov in Moscow added that Mr Maskhadov controlled no one in Chechnya "but his own bodyguards". ITAR-TASS meanwhile cited undisclosed Russian sources as saying that two warlords, Khattab and Mr Shamil Basayev, had threatened to execute Mr Maskhadov's family should he engage Moscow in peace talks.
Meanwhile, the UN Human Rights Commission yesterday passed a resolution calling on the Russian government to set up an independent inquiry into accusations of rights violations in Chechnya.
The resolution, calling for a "national, broad-based and independent commission of inquiry", was presented by the EU and supported by the US and several eastern European states.
Twenty-five members of the commission voted in favour, seven voted against, including Russia and China, and 19 abstained.
France has proposed to its G7 and EU partners that co-operation with Russia be conditional on Moscow's completion of economic reforms and its commitment to the rule of law.
The Finance Minister, Mr Laurent Fabius, and the Foreign Minister, Mr Hubert Vedrine, writing in yesterday's Financial Times, said they had proposed to the EU and the Group of Seven most industrialised countries a set of guidelines for co-operation with the government of Mr Putin.
France assumes the presidency of the EU in July.