Mikhail S. Gorbachev said a U.S.-Soviet treaty reducing long-range nuclear weapons could be signed by January but that he will not set aside disputes over the "Star Wars" program to reach such an accord.

The Soviet leader also said his policy of "glasnost," or openness, includes freedom of speech, but he condemned a leading dissident as a "parasite" and accused him of "sponging on the democratic process."Gorbachev's comments came in a pre-summit interview with two American news organizations. The Soviet news agency Tass on Sunday ran a partial transcript of the interview with The Washington Post and Newsweek.

Radio Moscow's English-language foreign service also carried a report about it as its lead item on Sunday. Soviet television's widely watched evening news program "Vremya" mentioned as its lead item that the interview had been published in Washington and would appear in Monday's Soviet newspapers.

The 90-minute discussion, in which Gorbachev also proposed a joint U.S.-Soviet trip to Mars, covered a wide range of foreign and domestic issues.

The interview, conducted in the Kremlin on Wednesday, produced a startling Biblical reference by the head of the officially atheistic state.

When asked about how far glasnost should go and about criticism of dictator Josef V. Stalin, the 57-year-old Communist Party leader said:

"Jesus Christ alone knew answers to all questions and knew how to feed 20,000 Jews with five loaves of bread. We don't possess that skill. We have no ready prescription to solve all our problems quickly."

The interview was conducted 11 days before President Reagan's arrival in Moscow for a five-day summit with Gorbachev. It will be their fourth meeting.

Although the Tass transcript included much of the interview, it deleted a reference to Yegor Ligachev, the Kremlin's No. 2 man. It also left out a reference to Gorbachev's wife, Raisa.

Ligachev, considered more conservative than the Soviet leader, reportedly wants to slow Gorbachev's policy of "perestroika," or restructuring, of the Soviet economy and society.

Gorbachev acknowledged a lively debate between the two but said "to present these discussions - which are a normal part of the democratic process - as division within the leadership would be a great mistake itself."

Gorbachev expressed optimism that a superpower agreement to cut strategic, or long-range, nuclear weapons will be completed by the time Reagan leaves office in

January. "We want to have that signed," he said.

If the agreement "comes to be drafted under the present U.S. administration, I see no reason why President Reagan and I should not sign it. I would certainly welcome that," Gorbachev added.

However, he cautioned that he has no plans to set aside disputes to hasten an agreement. "If we sign with one hand a treaty reducing strategic offensive forces in one area and at the same time launch an arms race in space or at sea, what would be the point? That would be senseless," he said.

He reiterated his opposition to Reagan's "Star Wars" missile defense program, known as the Strategic Defense Initiative, saying the leader who promotes an escalation of the arms race in space "is committing a crime against the people - his own people, and others."

U.S. and Soviet officials have said they don't believe the long-range nuclear weapons treaty will be completed by the end of Reagan's term.

Another treaty to ban short- and medium-range nuclear weapons is being debated by the U.S. Senate.

Gorbachev said he will ask Reagan at the summit to approve a joint Soviet-U.S. unmanned flight to Mars. "Why shouldn't we work together? We have great experience, you have great experience - let us cooperate to master the cosmos, to fulfill big programs," he said.