Armenia Seeks Alliance’s Help Against Azerbaijan : Conflict: Country threatens to leave Commonwealth of Independent States if members don’t defend it.

With its forces retreating under the Azerbaijani offensive in the disputed territory of Nagorno-Karabakh, Armenia warned Russia and other members of the Commonwealth of Independent States on Tuesday that it would quit the alliance unless they come to its defense under a recently signed mutual security pact.

Armenia, grasping for political leverage to compensate for its serious battlefield setbacks, also called upon the members of the Conference on Security and Cooperation in Europe to press Azerbaijan for negotiations and a political resolution of the escalating conflict.

Reports both from Yerevan, the Armenian capital, and from Baku in Azerbaijan indicate that the newest focus of the fighting appears to be a corridor linking Nagorno-Karabakh to Armenia.

The mountainous, predominantly Christian Armenian enclave within Azerbaijan had endured months of Azerbaijani attacks and a blockade until Armenian militias counterattacked and opened the corridor to Armenia last month.

“The Lachin corridor has come under heavy shelling, and Azeri forces are closing on it from both sides,” Samvel Dokholyan, an Armenian government official, said from Yerevan.

In Baku, the Azerbaijani capital, a spokesman for the Azerbaijani Popular Front confirmed the attacks on the corridor but said the Azerbaijanis had failed to break through. He said the assault will continue until it succeeds.

“Our goal is to restore a constitutional order on all of our republic’s territory,” front spokesman Ayaz Akhmedov declared. “That is why our armed forces are conducting operations to put an end to the supply of combat equipment to Karabakh from Armenia through the so-called ‘Lachin humanitarian corridor,’ which is chiefly used for military purposes.”

Akhmedov claimed substantial Azerbaijani gains in two districts, Askeran and Mordakert, that were the focus of the heaviest fighting Tuesday. But he maintained that there were few civilians in the villages.

The Armenian government, in response to the setbacks, announced on Tuesday the registration of all army reservists up to the age of 35 in anticipation of a full-scale military mobilization.

Felix O. Mamikoyan, the Armenian ambassador to Russia, charged that the Azerbaijani offensive, begun last Friday, was so intense that its goal could only be to drive Armenians out of Nagorno-Karabakh.

Appealing to Russia as Armenia’s ally and protector “from times immemorial,” Mamikoyan said that if Moscow did not respond, then Armenia would have to reconsider its membership in the Commonwealth of Independent States, which groups Russia, Armenia and nine other former Soviet republics, including Azerbaijan. Such a withdrawal would likely precipitate the organization’s collapse.

Under the recently concluded mutual security pact among most Commonwealth members, including Armenia but not Azerbaijan, “we should have received direct military assistance against Azerbaijani aggression,” Mamikoyan said.

In its own diplomatic thrust, Azerbaijan asserted that Armenia, through the success of Armenian militias over the past six months, was the true aggressor and that it was trying to undermine peacemaking efforts.

The Azerbaijani Foreign Ministry accused the Armenians of “scorched-earth tactics” to make the frontier uninhabitable.

Viktor K. Grebenshikov and Sergei Loiko of The Times’ Moscow Bureau contributed to this report.