Chechnya's biggest oil refinery complex burned out of control Friday after reportedly being struck by Russian bombers, and Chechen officials warned that the blaze could spread to a nearby tank containing 5,000 tons of explosive ammonia.

"If it catches fire, an ecological disaster will hit the entire North Caucasus," a Chechen Foreign Ministry official told Interfax news agency.The Vremya television program reported that rivers of oil were on fire, raising the possibility of damage to a critical pipeline built to pump Caspian Sea oil from Azerbaijan to the complex of three oil refineries in the Chechen capital of Grozny.

"The whole refinery complex is on fire, but the situation with the pipeline is unclear," said Marina V. Rodionova, press chief for the Russian Ministry of Emergencies. She said that only 10 to 20 tons of ammonia remain in the storage tank and that no evacuation of local residents is needed.

Later, the Russian Defense Ministry said an explosion could endanger human life within a radius of 1.2 miles, depending on wind and weather. Reports from Grozny said the ammonia tank is just 800 yards from the burning refineries, but no evacuation plans were announced.

Russian officials insisted that they had not bombed the oil complex.

"All oil refineries have been mined on orders of the Chechen leadership and can be blown up at any moment," a government press service statement said. "The refineries are protected by reinforced detachments of Chechen militants. Russian units that attempt to reach them will suffer heavy losses.

Whatever the cause of the refinery fire, Chechen officials said it has deprived nearby residents of one of their only sources of clean drinking water - melted snow.

City water supplies have been turned off for days, and people had been surviving by heating snow that is now covered with a black film of oil.

President Dzhokar M. Dudayev of Chechnya, reportedly holed up in a bunker under his presidential palace, appealed to Russian President Boris N. Yeltsin for a New Year's cease-fire starting at 8 p.m. Friday Moscow time.

For a second day, Dudayev announced that he is ready for peace talks with the Kremlin, but he told Vremya that he has one condition: no disarmament of the Chechen people. Moscow insists on disarming the separatist fighters it refers to as "criminal gangs" and "illegal armed formations."

The Kremlin's horrendous image problem worsened Friday as lawmaker Leonid N. Petrovsky returned from Grozny to report that Russian airplanes were shelling and bombing villages packed with terrified refugees.

In fighting Friday, two Russian soldiers were killed while foiling two nighttime attempts by Chechen commandos to break out of the encircled Grozny. That brought the official Russian casualty count to 52 dead and 132 wounded.

However, fueling already widespread rumors that the Russian military is hiding the true number of its dead, officers of the elite 34th Regiment Airborne Division in Pskov told reporters that losses were greater than had been officially announced.