Russian officials strove today to counter a growing impression that the campaign against Chechnya has hit the skids, reporting they have established new footholds in the southeastern part of the separatist region and regained control over two towns outside the capital that were hit by surprise rebel attacks.

But military officials acknowledged that Chechen rebels continue to hide out in many areas supposedly under Russian control, and said they could not preclude further attacks like the ones that embarrassed them Sunday. Some reports indicated that Muslim militants in Pakistan and Afghanistan were aiding the guerrillas with money and supplies.

The Russian military's steady progress during the first four months of the war has stopped in the past week, raising the prospect that the campaign that helped catapult Vladimir Putin to the post of acting president after Boris Yeltsin's resignation on Dec. 31 could now begin to undermine him.

The Russians claim to control roughly three-fourths of the rebellious region, but heavy fighting forced Russian troops on Friday to suspend air and artillery strikes on Chechnya's shattered capital of Grozny. Russian military leaders acknowledge they cannot win the war without capturing Grozny, and predicted today that bombs would eventually defeat the guerrillas there.

After backing away from the capital, Russian troops were stunned by rebel attacks Sunday in at least two Russian-controlled towns south and southeast of Grozny. Officials said today the Russian commander in Argun was lured to the town square, supposedly to talk to residents, then was shot and partially decapitated by waiting militants.

Another 10 soldiers died in Argun before the rebels were routed, according to Sergei Ivanov, secretary of the Kremlin's advisory Security Council. Other accounts reported a higher number of losses.

"We believed the elders that there were no bandits among them, but they let us down," Boris Maksin, chief of staff of the Interior Ministry troops, told the Russian Information Agency.

Russian officials insisted today that they have secured Argun and the nearby town of Shali, and that the rebels turned back before they reached Gudermes, the second-largest city in Chechnya.

The rebels disputed that claim on their Internet site, saying they hold some roads and buildings in the area.

Defense Minister Igor Sergeyev said today the setbacks are only temporary and that the Russian military strategy remains the same--except that soldiers will now try harder to identify militants hiding among civilians. He said the Russians are no more willing to negotiate with the rebels now than before, asking: "With whom is one to talk?"

Military experts say that to secure peace, Putin ultimately will be forced to find a political solution to the conflict, even if he has to negotiate with a round table of Chechen warlords. Otherwise, "the war could go on for three, four or five years," said Dmitri Trenin, a military expert with the Carnegie Endowment for International Peace in Moscow. "There can be no purely military victory in Chechnya."

Trenin said the Russian military now risks losing its momentum, and popular support for the war along with it. "They need to do something with Grozny in the [next] few weeks, because time is beginning to work against them," he said.

Today's reports looked somewhat better for the Russians. The rebels said on their Web site that they had withdrawn from Vedeno, a key mountain stronghold in the south. The Russians claimed to have surrounded Vedeno and the nearby town of Shatoi, and to have captured a third of the strategically important Argunskoye gorge.