Chechen Rebels Admit Losing Stronghold to Russians : Caucasus: Separatists say they have regrouped since being routed from mountain headquarters.

Separatists in Chechnya said Monday that they had lost the mountain town of Vedeno, their military headquarters since early spring, and were being forced into a hit-and-run struggle against Russian troops after six months of positional warfare.

Russian jets destroyed Vedeno’s command post Wednesday and paratroopers seized the town late Saturday. After a day of denials, a Chechen spokesman admitted the defeat but said the separatists had regrouped elsewhere and were taking “effective steps” against the Russians.

As fighting continued across Chechnya’s mountainous southern edge, separatists shot down a Russian MI-24 assault helicopter Sunday near the town of Nozhai-Yurt, killing its two crew members, the Defense Ministry in Moscow reported.

The loss of Vedeno was a serious tactical and morale setback for the forces of Gen. Dzhokar M. Dudayev, who was elected president of the tiny Muslim republic in southern Russia in 1991 and declared independence. Russia sent tens of thousands of troops to Chechnya on Dec. 11 to crush the separatist movement and by late January had driven Dudayev and his fighters from their lowland capital, Grozny, at an estimated cost of 20,000 lives.

Grudgingly, the separatists have since abandoned every town and village on the plains in a southward retreat into the Caucasus Mountains, where they once claimed to be invincible.

But the brief battle for Vedeno showed they can be no more certain of defending fixed positions in the highlands, which occupy one-fifth of the republic, than they were on the plains.

Vedeno, 38 miles southeast of Grozny, had been chosen as the separatists’ alpine command center because of its 8,200-foot altitude and historic significance as a bastion of resistance against Moscow.

Nestled in a mountain gorge among beech trees and evergreens, Vedeno was the last stronghold of Imam Shamil, who fought to create an independent Islamic state in the Caucasus and resisted the Russian army for four decades before surrendering in 1859. Ruins of his 20-foot-high white stone fortress still stand in the center of town.

Shirvani Basayev, a Chechen commander, boasted in an interview in Vedeno early this year that if the Russians ever tried to storm the town, “that’s the end of them. We’re on our land, which feeds and nourishes us. And we have nowhere to retreat.”

But the Chechen high command and several hundred fighters apparently withdrew before Saturday’s assault to defend a hill overlooking the town. Col. Gen. Anatoly S. Kulikov, the Russian commander, said his troops entered Vedeno from a different direction, “practically without resistance or bloodshed.”

The Russians said they seized eight tanks, 28 truckloads of ammunition, two pieces of artillery and six Chechen prisoners.

Kulikov was shown on Russian television descending from a helicopter in Vedeno and meeting with townsfolk Sunday while a Russian flag flew over the bus station. He formed a local militia and promised to deliver humanitarian aid to civilians.

The separatists were pushed five to six miles south of the town, the Russians reported.

Ruslan Galayev, a Chechen commander, told the Russian news agency Itar-Tass that Dudayev and his top commander were controlling their forces from an undisclosed location. He said the loss of Vedeno would force them to switch from direct confrontation to guerrilla warfare.

Despite the setback, there is no sign that the tough, resourceful Chechen guerrillas, believed to number 7,000, are ready to give up. Vastly outgunned and outnumbered, they have punished the Russian army for every mile of its advance.

In Moscow, the International Committee of the Red Cross delegate, Thierry Meyrat, said at least 280 Chechens and 90 Russians were being held by the opposing forces as prisoners of war. He told reporters that both sides were also taking civilian hostages, mistreating their captives and laying antipersonnel mines--all in violation of international laws of war.

The Russian side has committed the bulk of the violations, Meyrat said, but a Red Cross mission in Chechnya has discovered one outlawed practice committed exclusively by the separatists--conscripting boys younger than 15.