WASHINGTON — Senate Majority Leader George J. Mitchell said Thursday that he lobbied President Bush to hold this spring’s superpower summit at the first family’s summer compound in Kennebunkport, but rising tensions in Lithuania could derail hopes for a conference on Maine’s coast.

Mitchell will extend an invitation to visit Maine to President Mikhail S. Gorbachev in Moscow this weekend, along with a warning not to crush Lithuania’s independence movement. He is leading a Senate delegation that will depart Friday for talks with Gorbachev and the leaders of Russia’s parliament.

If the United States and Soviet Union still are at loggerheads over Lithuania, the Washington Post reported, Bush and Gorbachev are likely to hold a “businesslike” summit in Washington, with little or no outside travel.

A relaxation of tensions would make a Kennebunkport visit more likely, other Washington sources speculated.

At a press conference with Republican Senate Leader Robert Dole, Mitchell said that Russian leaders warned them that Gorbachev is facing growing pressure among his own supporters to act tougher on Lithuania. That comes at a time when both branches of the U.S. Congress are demanding that President Bush crack the whip on Gorbachev for attempting to “intimidate” Lithuania’s independence movement.

The White House on Thursday set the dates, but not the location, of Bush’s second summit with Gorbachev. It is scheduled to begin Wednesday, May 30, and conclude Sunday, June 3.

“The location still is up in the air,” a White House press spokesman said. The first Bush-Gorbachev summit was at Malta last December.

Aides said that Mitchell raised the issue of a Maine summit with Bush Thursday afternoon, but got no indication one way or the other.

According to the White House’s tentative schedule, the first family will be in Kennebunkport May 25-28. Gorbachev has agreed to give the commencement address on May 28 at Brown University in Providence, R.I., which is a relatively short hop from Kennebunkport.

Congressional aides said that Mitchell and Sen. William S. Cohen, who both graduated from Bowdoin College, considered inviting Gorbachev to give a speech at their alma mater, but Mitchell said that nothing came of the plan.

“I think it would be very helpful for Mr. Gorbachev to visit Maine. National leaders tend to lead isolated lives. I would like to have him see as much as he could take in of the country,” Mitchell said.

Mitchell said Soviet Foreign Minister Eduard Shevardnadze indicated that Gorbachev does not intend to use military force to crush Lithuania’s bid for independence. The Senate leaders met privately with Shevardnadze Wednesday night.

They suggested that Gorbachev has a growing image problem among many Russians for his failure to crack down on Lithuania and the other restive provinces.

Shevardnadze “expressed to us … the intention of the Soviet government to resolve the (Lithuania) matter by dialogue, through negotiation without resort to force. He expressed confidence in their ability to achieve that objective,” Mitchell said.

A resort to military force, according to Mitchell, “would undoubtedly provoke a strong reaction in the Congress.” The Soviet foreign minister, Mitchell said, made it clear that condemnation by the U.S. Congress would not guide Gorbachev’s policies.

“Their approach is based on what they think is the right approach in their interest and they have concluded as a matter of policy that a process which did not involve use of force is in their best interest and that’s why they’re doing it, not as a result of what they anticipate our reaction might be,” he said.

According to Dole and Mitchell, Shevardnadze warned the senators that Gorbachev and his leadership came under direct attack at several meetings by critics who said the Russian president “was not being strong and forceful” in dealing with Lithuania.

“By inference,” Dole said, Shevardnadze warned that if Gorbachev is not successful in working out the problems he faces “(he) could be gone.”

Mitchell said that Lithuania is just one of “a wide range of problems” now confronted by Gorbachev. “If things break down he might be replaced,” Mitchell warned.