Thousands Mourn in Azerbaijan : Soviet Union: Marchers in Baku protest last weekend’s army assault. Some burn their Communist Party cards. The republic’s Parliament threatens secession.

Sirens wailed Monday in Baku, the capital of Azerbaijan, as hundreds of thousands of Muslims poured into the streets in a massive funeral procession for the people killed when Soviet troops burst into the city to put a bloody end to a nationalist uprising.

At the same time, the ceremony was a protest demonstration, with Azerbaijanis burning their Communist Party membership cards or tossing them into garbage pails and holding up placards opposing the Soviet party and President Mikhail S. Gorbachev, participants said. One banner showed a picture of Gorbachev with crossed bones and the words: “Executioner. Who Is Next?”

Soviet soldiers kept watch from a distance and did not interfere. These were the same troops who had stormed into Baku before dawn Saturday, breaking through human blockades with tanks. For three days, citizens manning makeshift barricades had kept them from entering the city.

The troops were sent to Baku after at least 72 Armenians had been killed in violent disturbances that began Jan. 13.

“The arrival of the army has changed Baku beyond belief,” the government daily Izvestia said in a dispatch Monday from the Azerbaijani capital. “The city lives under horrible tension. The shoulders of highways are littered with twisted remnants of trucks, buses and passenger cars used before Saturday to block the army from entering. The remnants are covered with flowers.”

It is becoming increasingly clear that in the days ahead, Moscow will have a difficult time reasserting its authority over Baku, whose residents are increasingly calling for separation from the Soviet Union.

The Azerbaijani Parliament, which met in emergency session from 2:30 a.m. to 7 a.m. Monday, declared that if the Soviet troops do not leave Baku within two days, it will begin constitutionally sanctioned procedures to secede, Arif Unisov, a member of the nationalist Popular Front, said in a telephone interview.

The legislators condemned the army action as unnecessarily brutal, Unisov said, adding that among the dead were children and a doctor who had been trying to help the wounded. He said Baku citizens need not heed the Kremlin’s emergency regulations, which among other things impose a nighttime curfew.

Azerbaijanis, predominantly Muslim, and Armenians, who are mostly Christian, have fought fiercely for two years for control of Nagorno-Karabakh, a mostly Armenian enclave within Azerbaijan.

But last week’s ethnic violence in Baku, in which some Armenian victims were tossed from balconies and others were burned alive, was the bloodiest yet.

Gorbachev, in a speech to the nation Saturday night, said the pogroms launched by extremists have put the army in an untenable position, leaving it with no choice but to use force. He said he hopes the country will understand.

Armenian and Azerbaijani party and government leaders agreed in negotiations Monday to remove armed groups from the border between the two republics, to restore damaged communication lines and to resume railway traffic, the official Tass news agency said Monday night.

It was not immediately clear, however, whether the armed militants on both sides will abide by those accords.

During the military sweep into Baku, a Caspian Sea port city of 1.8 million people, at least 83 people, including 14 servicemen and members of their families, were killed, according to the latest official figures, which have risen daily. Azerbaijani activists say the death toll is much higher, 500 or more.

Independent confirmation has not been possible. Foreign journalists have not been allowed to enter Baku since the violence began.

Sporadic gun battles continued Monday on the northern edge of Baku between the Soviet army and nationalist resistance fighters, Azerbaijani journalist Nazim Ragimov said in a telephone interview.

“The Soviet troops at this point seem primarily interested in protecting the Communist Party and republican government buildings,” he said.

The evacuation of families of ethnic Russian army officers continued from Baku “because no one can guarantee their safety,” the main evening news program “Vremya” said.

In an effort to put an end to sniping, the military command in Baku announced that citizens have been given two days to surrender their weapons, together with assurances that those who do so will not be punished.

But residents have made it clear that they do not intend to respond to army demands or requests. Rallies Sunday and the funeral procession Monday were in open defiance of the state of emergency, which bars public gatherings.

Gorbachev’s policies came under fire from Armenians and Azerbaijanis alike Monday. Armenian Patriarch Karekin II, speaking in Nicosia, Cyprus, said Soviet indecisiveness and inaction over a two-year period led to an escalation of the dispute between the two peoples.

“I think that from the very beginning, the supreme authorities in the Soviet Union should have tackled the issue more effectively,” he said.

In Moscow, hundreds of Azerbaijanis gathered in a protest at their republic’s mission. An Azerbaijani leader, Assim Mamedov Asad-Zade, told them: “Gorbachev said he was building a bright future. Can it be built on the blood and corpses of our people?”

Monday’s procession in Baku started at Freedom Square, which until a few days ago was Lenin Square. Citizens dressed mostly in black walked from the square to the hilltop Kirov Park, where 119 graves had been dug. It was not immediately clear how many were buried, but Yusif Bagirov, an attorney and member of a commission set up by lawyers to investigate the army action, said he had counted 94 coffins being carried through the streets.

Throughout the morning, ambulance sirens, car horns and factory whistles were sounded. Factories have been closed in a protest strike.

“We are going to strike until the Soviet army leaves,” said Elmira Akhmedova, a journalist working with the republic’s Ministry of Culture. “The Russians will find here a dead city.”

Mourners waved black flags and carried pictures of the dead, who are regarded as martyrs. “All the people of Azerbaijan are in tears,” Baku Radio said.

While some publicly disposed of their Communist Party membership cards, the city’s spiritual leader, Sheik Ul Islam, threw away the card that identifies him as a member of the national Congress of People’s Deputies, Unisov said.

Ul Islam also issued a statement condemning the army’s incursion into Baku, according to the republic’s official news agency, Azerinform.

“No one, including the people of Azerbaijan, should be talked to with the language of guns,” Ul Islam was quoted as saying. “There is no justification for this crime.”

Unisov, the Popular Front member, said that not all the dead were buried Monday. Many people, including his neighbors, he said, buried their dead Saturday and Sunday. He said some people are still listed as missing, although they were thought to have been killed Saturday.

The Azerbaijan Parliament set up a commission Monday to try to establish what happened to those listed as missing, Unisov said.