New Soviet Troops Land in War Zone as Fighting Grows : Ethnic strife: Fierce clashes erupt between Armenian and Azerbaijani militias armed with advanced weapons.

Fighting intensified between Armenian and Azerbaijani militias in the southern Soviet Union on Tuesday despite Moscow’s imposition of a state of emergency and the arrival of more than 11,000 additional peacekeeping troops in the region.

Fierce clashes, involving hundreds of combatants on both sides, erupted repeatedly, according to Soviet news reports, as reinforcements reached the groups of Azerbaijanis and Armenians who have been battling one another in the foothills of the southern Caucasus Mountains for many months.

Using rocket launchers, large-caliber machine guns, anti-aircraft artillery and even captured armored vehicles, they fought skirmish after skirmish around Nagorno-Karabakh, an enclave of Christian Armenians in Muslim Azerbaijan, and along the Armenian-Azerbaijani border.

In both the Armenian capital of Yerevan and in Baku, the Azerbaijani capital, the newly formed militias were raiding police stations and ordnance depots for arms, forming contingents and moving into the hills, according to central government officials.

“We cannot bring ourselves to pronounce it aloud, but what is happening now in Karabakh and in northern Azerbaijan can be termed unambiguously a civil war,” the correspondent of the youth newspaper Komsomolskaya Pravda wrote, reflecting the sharp apprehension that even the central government’s new measures will not halt this conflict.

Armed with their stolen weaponry, the Armenian and Azerbaijani militias were attempting to capture key hilltops and ridges dominating the region’s rugged terrain in preparation for what could become a bitter mountain war if they choose to continue the struggle.

The conflict is not yet a civil war, Gennady I. Gerasimov, the Foreign Ministry’s chief spokesman, contended, and the government is determined to end it before it becomes one.

“Civil war occurs when two parts of a country are fighting each other,” he commented. “Moscow has stepped in to stop this. It is national strife . . . let’s say almost a civil war.”

After six days of fighting, the death toll was officially put at 56 Tuesday, but front-line reports from Soviet correspondents spoke of scores more casualties--killed, wounded and captured--in the growing conflict. One dispatch from Stepanakert, the administrative center of Nagorno-Karabakh, said that 20 people, including two soldiers, had been killed there in the current fighting.

The government, reporting on the implementation of the state of emergency declared Monday, said that 6,000 more internal security troops, supported by 5,000 soldiers from the Soviet army, were airlifted into the region Tuesday. The statement did not disclose the total number of troops deployed in the region.

The security forces, local police as well as the internal troops and regular soldiers, were given firm instructions by the Communist Party’s top leadership Tuesday to take tough, uncompromising measures in restoring order and not to hesitate in using their weapons when confronted by armed resistance.

“If fired upon, our men have been ordered to shoot back,” a senior officer from the Interior Ministry said after the strategy session in Baku attended by Yevgeny M. Primakov, a key adviser to President Mikhail S. Gorbachev, and other senior party officials Tuesday. “If this conflict is to be stopped, resolute actions must be taken--and we are prepared to act.”

The official Soviet news agency Tass, reporting from Baku on Tuesday evening, said: “Appeals for reason have produced no result. The situation in Azerbaijan continues to remain extremely tense.”

Strikes, Rallies Banned

Soviet authorities, meanwhile, began implementing other parts of the state-of-emergency decree by banning political rallies, demonstrations and strikes, suspending the activities of nationalist groups, restricting entry into the region and traffic within it and controlling news coverage.

Security forces also began detaining without charge those suspected of involvement in the feuding or of violation of the state-of-emergency regulations. They can be held for 30 days.

In Nagorno-Karabakh, security forces detained, at least briefly, 26,000 people, roughly a fifth of the population, the Interior Ministry told the government newspaper Izvestia, and seized more than 3,000 guns and other weapons.

A commentator in Izvestia justified the stringent measures as necessary to protect the political and economic reforms undertaken by Gorbachev, whose leadership is now being put to one of the cruelest tests he has faced in the past five years.

“ Perestroika has been forced to defend itself,” the Izvestia commentator, Albert Plutnik, wrote in a front-page article, emphasizing the political primacy of Gorbachev’s program for political, economic and social restructuring. “And it is not its fault that, if to defend itself and others, it requires the help of emergency measures.”

But there was no indication of any further efforts to reach a political settlement, not even at the national level, although senior Communist Party officials from Moscow remained in both Baku and Yerevan.

“The escalation of violence continues,” an Izvestia correspondent wrote from Baku, noting that despite all the meetings, discussions and statements issued in the past two days, the attacks are continuing.

The central government had spent nearly two fruitless years attempting to negotiate a compromise over the root issue of the future of Nagorno-Karabakh, which has been administered by Azerbaijan since 1923 although most of its 160,000 residents are Armenian and want to be part of Armenia.

Nagorno-Karabakh is an emotional issue for both the Armenians and the Azerbaijanis. Both claim that the region is part of their historic homeland; both accuse the other of bias, bigotry and even oppression; both feel that Nagorno-Karabakh has now become a test of their national pride.

For Armenians, the threat that they perceive is so reminiscent of the 1915 attacks upon them by Turks that to them, the issue is their survival as a nation.

The Armenians continued Tuesday to arm themselves as fast as they could, raiding 16 police stations and military warehouses to get weapons. At one outlying station, they seized 106 Kalashnikov assault rifles, 30 carbines, 217 small-bore rifles, 11 revolvers and a grenade launcher, according to Tass. At another, they got 83 Kalashnikovs, 383 shotguns and 111 small-caliber rifles.

The Azerbaijanis, meanwhile, were attempting to capture more armored vehicles, including battle tanks taken from soldiers, for an arsenal that already includes armored personnel carriers, heavy mortars and anti-aircraft guns.

Most of this equipment was given immediately to volunteers for the rival militias, and they were sent quickly to “the front,” as Armenians and Azerbaijanis were coming to think of the battle zone.

Although most of the additional government forces were being deployed in the heavily contested Khanlar and Shaumyan districts north of Nagorno-Karabakh, the fighting raged on there, according to correspondents for Tass and Radio Moscow.

In those districts, groups of up to 300 men on each side continued to fight, according to Tass and other press reports. More than 2,000 men, believed to be Azerbaijani nationalists, have taken up positions on the hilltops around much of Nagorno-Karabakh and, using anti-aircraft guns, have made it difficult for helicopters to land.

Troops, both from the internal security forces and the Soviet army, were also dispatched to Baku, the Azerbaijani capital, in an effort to halt the continuing attacks by militant Azerbaijani nationalists there on Armenians in what officials described as “a murderous pogrom . “

Baku was described by Tass and Izvestia as still very tense, with groups of Azerbaijanis roaming the city in search of Armenians, beating and sometimes killing them and then looting their apartments. Nearly 1,000 Armenian flats, including those of army officers, were ransacked and looted by the Azerbaijani nationalists, according to police figures.

Most of those reported killed so far are believed to be Armenian residents of Baku, which once was home to 200,000 Armenians but which had only 20,000, mostly elderly, when the attacks against them began over the weekend.

Baku authorities have established special shelters--in movie houses, police stations, military barracks and schools--for the city’s remaining Armenian residents, most of whom are awaiting evacuation to Yerevan.

And the nationalist Azerbaijani Popular Front, widely accused in Armenia of making the political calls that directly led to this violence, sent escorts to find the Armenian residents before the roving gangs did and to escort them to safety.