MOSCOW, OCT. 8 -- Soviet President Mikhail Gorbachev today urged the Communist Party leadership to come to terms with radical economic reforms, including the privatization of property and enterprises, and warned that the country is in danger of disintegration under the pressure of secessionist movements in the country's republics.

Speaking at the first session of the party's policy-making Central Committee since the 28th Communist Party Congress in July, Gorbachev tried to steer the body toward a far more progressive position than it has shown in the past. Although many of the members are traditional party bosses, some, such as independent historian Roy Medvedev are new to the committee and seen as more liberal.

Gorbachev said that "the inertia of old thinking is a real danger to the party." In a statement that seemed to criticize not only the late dictator Joseph Stalin but also the founder of the Soviet state, Vladimir Lenin, Gorbachev said: "All our previous ideology presented socialism as an opposite to the market and viewed the recognition of a market as an encroachment on socialism.

"Yes, we are encroaching on socialism, but only the socialism that was built bureaucratically, under which the country veered off the path it embarked on in 1917," he said.

Gorbachev promised that the reform program he will send to the legislature Oct. 15 "will not be some kind of compromise document with rounded corners and fuzzy positions" nor will it threaten the principles of socialism. Gorbachev has endorsed a radical "500 Days" program to transfer the country from a centralized system to a market economy, but he said he is also trying to include elements of a more conservative program drafted by Prime Minister Nikolai Ryzhkov.

"A market," Gorbachev said, "will allow us to realize the socialist principle -- from each according to his abilities, to each according to his work."

Gorbachev said that the continued failure of the Soviet economy must be blamed on the state's traditional monopoly on property "which makes it no one's property." Although the state will continue to control such industries as energy, transportion, communications and defense manufacturing, Gorbachev said the reform program would allow for different forms of property.

In his speech, Gorbachev also focused on the many movements around the country demanding varying degrees of independence for the nation's republics. Gorbachev blamed ethnic strife for causing economic as well as political problems.

"Let's be frank," he said. "If these tendencies are not overcome and are allowed to develop further, the country really could be threatened with its own Lebanonization with all the accompanying consequences."

Gorbachev said "separatists" were causing an "atmosphere of hatred and terror," adding that "in these conditions people are afraid to say what they think."

This year, the legislatures in nearly all of the Soviet Union's 15 republics have issued declarations of sovereignty or independence. Gorbachev is hoping that the drafting of a new treaty of the union giving the republics greater economic and political independence will hold the union together.

But republican leaders such as Boris Yeltsin of Russia, Vytautas Landsbergis of Lithuania and Levon Ter-Petrossian of Armenia agree that the Kremlin is not prepared to cede enough authority. Negotiators are still dealing with at least a dozen radically different drafts of a new treaty of the union. The Baltic republics have already entered into preliminary negotiations with Moscow on complete independence.

Vladimir Ivashko, the former Ukrainian party chief who became Gorbachev's deputy general secretary in July, told the Central Committee that "the union no longer exists -- not in its old form, and not yet in its new one. There is no use lamenting a unitary formation that has outlived its purposes. It is necessary to move forward towards setting up a new federation of sovereign states."

Ivashko told the meeting that 681,000 people have quit the Communist Party in 1990 -- nearly half of them in the wake of the party congress when Yeltsin and several other leaders, including the mayors of Moscow and Leningrad, resigned from the party.

According to Communist sources, the party's daily newspaper Pravda is in a state of crisis. Many of the younger journalists at Pravda have criticized editor Ivan Frolov, a Gorbachev confidante, of making the paper too dull and conservative. At a stormy editorial board meeting last week, Frolov said he would resign if necessary after the Central Committee session. As other newspapers here grow more interesting and daring, subscriptions to Pravda have plunged.