Russian troops suffered new losses battling Islamic separatists in the steep mountains and caverns of western Dagestan today as the week-old conflict appeared to be intensifying.

In a night of airstrikes against the Islamic insurgents, who have seized control of several Dagestani villages, Russian troops lost four paratroopers, bringing the total dead to 14, with 27 wounded. The insurgents said five of their combatants have been killed, while Russian officials said they have killed 200 or more.

The conflict was triggered last weekend when the insurgents, led by Chechen guerrilla leader Shamil Basayev, crossed from Chechnya into Dagestan, a neighboring Russian region. Chechnya fought a two-year war against Russia for independence that ended in 1996 with the withdrawal of Russian troops and a cease-fire, but Chechnya's permanent status was unresolved.

Basayev has said he wants to expel Russian troops from Dagestan, a multi-ethnic region that borders the Caspian Sea. But for now, the rebels appear to be fighting to hold mountain villages on the Dagestani side of the border around the town of Botlikh.

Russian Interior Ministry forces were quoted today as saying the rebels hold seven villages in the area. The Russian troops have been using helicopter gunships and warplanes to try to dislodge the insurgents, and made 19 missile and bomb strikes on them overnight. At least one of the attacks was aimed near the village of Kenkhi, on the Chechen side of the border with Dagestan.

Acting Prime Minister Vladimir Putin, who faces a confirmation vote in parliament Monday, had promised that Russia would carry the conflict into Chechnya if necessary, but so far the military activity appears to be in Dagestan. Up to 6,000 civilians reportedly have fled to the homes of friends and relatives in the Dagestani capital, Makhachkala, a grimy port city on the Caspian.

Russia has said that mercenaries from the Middle East are aiding Basayev's men, who number more than 1,000. Foreign Minister Igor Ivanov sent a letter today to U.N. Secretary General Kofi Annan with copies to the foreign ministers of the other seven Group of Eight nations, European Union nations and to the chairman of the Islamic Conference Organization, appealing to them to stay out of the conflict. Russia has "indisputable evidence" of outside help, he said, adding that "any forms of support for the terrorists and their actions will be regarded as crude interference in Russia's internal affairs with all the possible consequences."

After the disastrous Chechen war, in which tens of thousands of soldiers and civilians were killed, many Russian politicians want to avoid another calamity in the North Caucasus, especially as parliamentary elections approach. Grigory Yavlinsky, leader of the centrist Yabloko bloc in the Duma, the lower house of parliament, called for a harsh response to the incursion, saying it was "direct aggression" against Russia.