More than 80 Russian soldiers died when a giant military helicopter crash-landed in Chechnya on Monday after a possible guerrilla attack, local media reported. The Mi-26 helicopter, packed with more than 130 troops, plunged around 600 feet into a minefield on the edge of its destination -- Russia's main Khankala military base which lies a short distance from the regional capital Grozny.

Sappers had first to clear a path to the blazing wreckage, which was still billowing smoke hours after the disaster, before they could haul survivors from the wreckage, Russia's Deputy Prosecutor General Sergei Fridinsky said.

"From the scene of the accident several dozen injured and dead have been evacuated, but we do not know the exact number of victims," Interfax quoted him as saying.

Itar-Tass news agency quoted a source at Khankala military headquarters as saying 85 soldiers had died. State-run ORT television said that would make it Russia's worst-ever military air disaster. Russian officials declined to give any death toll.

Defense Ministry spokesman Nikolai Deryabin said an engine fire had forced the pilot to make an emergency landing, but Chechen nationalist fighters battling invading Russian troops for independence were quick to claim an important military victory against the "occupying forces."

"With the help of a Zenit missile, a Russian Mi-26 transport helicopter was shot down," the Chechen nationalist Web Site www.chechenpress.com said in a statement next to a photograph of the Mi-26 in flames.

The Chechen nationalists' version was confirmed by a Russian military source who told Interfax: "It would appear that the helicopter was shot down by a Zenit missile."

PUTIN ORDERS A THOROUGH INVESTIGATION

The deputy commander of Russia's forces in Chechnya, Boris Podoprigora, said of the 132 people on board, 32 were in the local military hospital but "their lives are not in danger."

"Right now, almost all personnel from the hospital are working at the site...Rescue work is going on under difficult circumstances," he told Russian television.

President Vladimir Putin, who sent Russian troops back to Chechnya in October 1999 after a three-year absence, was being kept informed of developments, the Kremlin said.

"I would like to receive fresh information about the incident in Chechnya," he told RTR state television. "This catastrophe should be thoroughly investigated and we should send a competent commission there as soon as possible."

Agencies said General Nikolay Kormiltsev would head the crash commission into the accident, adding that Viktor Kazantsev, the Kremlin's envoy to the region, was also flying to the accident site.

Two soldiers reported seeing ground fire directed toward the helicopter before the crash, and the prosecutor general's office launched a probe into what he calls terrorism and premeditated murder, agencies reported.

Defense Minister Sergei Ivanov sent a telegram of condolences to the families of the dead, and vowed his ministry would do all it could to help them.

The Mi-26 helicopter, one of the largest in serial production, began flying in the 1980s with an official capacity of 80 combat-equipped troops, according to the authoritative Jane's All the World's Aircraft. It has a payload of 20 tons and is more than 130 feet long.

Russian forces have struggled to subdue the Caucasian province of Chechnya despite a massive military occupation. Clashes with nationalist fighters usually increase during the summer when thick forest cover makes it easier for them to hide.

Smaller Russian Mi-8 helicopters are often targeted by the fighters, but they rarely carry large numbers of passengers.

Russia returned to Chechnya in 1999 after a first 1994-96 war handed the region de facto independence.