Latest Truce Collapses in the Caucasus : Conflict: Armenia and Azerbaijan each blame the other for violating accord brokered by Moscow.

A cease-fire agreement between Armenia and Azerbaijan collapsed in gunfire and artillery salvos Saturday, frustrating Russia’s latest attempt to end the bloody conflict on its southern border.

It was at least the sixth time that a truce between the two feuding Caucasus republics failed to hold.

Air Marshal Yevgeny I. Shaposhnikov, commander in chief of the Commonwealth of Independent States, said that he has now sent telegrams to the leaders of the two states proposing that they ask the Commonwealth to send peacekeeping troops to Nagorno-Karabakh, an enclave within Azerbaijan but populated mostly by Armenians, that lies at the heart of their conflict.

“We will take this step, if it is necessary for them,” Shaposhnikov declared, according to the Interfax news agency. His statement is a sign of Moscow’s stiffening resolve to halt the longest-running outbreak of ethnic strife on the territory of the former Soviet Union.

The latest cease-fire accord, brokered by the Russian defense minister, Gen. Pavel S. Grachev, was reached Sept. 19 by the Armenian and Azerbaijani defense ministers at talks hosted by Russia in the Black Sea resort of Sochi.

The truce was supposed to halt the fighting in an undeclared war that, according to the United Nations, has claimed more than 3,000 lives and created half a million refugees in the past 4 1/2 years.

At first, the cease-fire appeared to be working, though tardily. It was supposed to go into effect at midnight Friday. By 4 a.m. Saturday, the Russian Defense Ministry said hostilities had stopped, with only occasional shots heard in the Azerbaijani border region of Tauz.

But Armenian and Azerbaijani officials disputed Moscow’s claims almost immediately, and it soon became obvious that, at best, there had only been a brief lull in fighting between the Caucasus Mountain neighbors.

“The Mardakert and Askeran regions (in Nagorno-Karabakh) are under heavy shelling. The Azeris are using Sukhoi 25 warplanes, helicopters, tanks. They are only talking about peace,” Satenik Akopyan, editor of Armenia’s Armenpress news agency, said from the Armenian capital of Yerevan.

“The Armenian side violated the truce,” countered Vagif Rustamov, director general of Azerbaijan’s official Azerinform agency, who spoke from Baku, the Azerbaijani capital.

Azerbaijani Defense Minister Ragim Kaziev, in a statement, blamed the Armenians for failing to exchange the required information on how a disengagement and pullback from the “conflict zone” foreseen by the cease-fire would be carried out.

Envoys of Kaziev and his Armenian counterpart, Vazgen Manukyan, met in Moscow last Friday to devise a way to put the cease-fire into effect. But officials from Nagorno-Karabakh, which now claims to be independent, were not invited to Moscow or Sochi.

“We still think that any document signed without the participation of the legally elected authorities of the Karabakh Republic is invalid,” Manvei Sarkisian, a Nagorno-Karabakh representative, told the Associated Press.

The Azerbaijani Defense Ministry accused Armenia of violating the truce when it was only 50 minutes old by opening fire on two Azerbaijani villages, the Russian Information Agency said. Snark, an Armenian agency, said Azerbaijani forces opened fire after midnight on three villages in the Goris region of Armenia.