SOFIA, BULGARIA, NOV. 29 -- Bulgaria's Socialist prime minister, Andrei Lukanov, resigned today with his cabinet of former Communists under pressure from a general strike and mounting street demonstrations.

In a televised speech, Lukanov said he was stepping down because he had not been able to assemble the political consensus necessary to implement free-market reforms. He denied that he was resigning under public pressure and argued that only a coalition government of Socialists and the anti-communist opposition can save Bulgaria from economic collapse. The country is burdened with a $10.6 billion foreign debt and has lost more than $1.7 billion as a result of the international embargo against Iraq. Bulgaria's foreign trade has plummeted.

Thousands of opposition supporters in the capital greeted the government's resignation with roars of celebration, honked their car horns and chanted, "Bye-bye, BKP," for Bulgarian Communist Party, the ruling party that changed its name to Socialist and won the country's first postwar free election in June.

"It is the end of an epoch and the beginning of our revolution," said Ivan Ivanov, a 31-year-old engineer in the crowd. Throughout the afternoon the state radio and television stations, whose employees had joined the strike, played records by the Beatles. Students drove a truck carrying a piano through the streets singing "Let It Be," the theme song of the month-long campaign to unseat the government.

Lukanov has headed Bulgaria's government since helping to plot the overthrow of former dictator Todor Zhivkov in a palace coup last November. Until then, he had been minister for foreign economic relations. Since the June elections, his term has been marked by paralysis in the legislature, food shortages and deepening financial crisis.

A spokesman for President Zhelyu Zhelev, a former leader of the opposition Union of Democratic Forces (UDF), said the heads of all parties met today and agreed that a new coalition is needed. But neither the president nor Lukanov defined how a new cabinet would be composed or who would be the new prime minister.

Zhelev, who has taken on the role of mediator, stressed that the legislature should turn its attention at once to drafting a new constitution. The UDF, the main opposition coalition, walked out of the National Assembly last Friday.

Forming the new government may prove difficult, with both the National Assembly and the country polarized. "We have enormous problems ahead of us which will not be easy to solve, whoever takes power now," said opposition supporter Ivanov.

The general strike that brought down Lukanov's government was called Monday by the right-wing labor union Podkrepa. Initially weak, it grew through TV and radio support, eventually disrupting transportation, oil production and natural gas supplies. Today the former Communist labor federation, Bulgaria's largest, joined the strike, making it decisive.

Daily street demonstrations were also organized, culminating in barricades set up at Sofia's main intersections and around the National Assembly building.

Lukanov's speech was followed by an announcement from Podkrepa that it was ending the strike. The program closed to the sound of Pink Floyd's anti-authoritarian anthem "The Wall."

Some former Communist Party members appeared to fear retribution now that they may have lost the government's protection. Bulgarian television reported that two passenger aircraft took off from Sofia's airport today on unauthorized routes and failed to respond to air traffic controllers. One headed toward Greece and the other to Plovdiv, east of Sofia. On Wednesday, Podkrepa demanded that all foreign air carriers leaving Sofia should provide passenger manifests four hours before takeoff so the union could check for would-be escapees.

Only a half-dozen aging Socialist supporters gathered outside the party's headquarters today to mourn its loss of the second life it was given in June's elections. The rest of the capital's flag-waving, chanting crowds seemed to accept Lukanov's removal as the popular success they missed a year ago.