The Soviet Union is "trying to capitalize" on the worldwide nuclear freeze movement and its agents "were actively involved" in planning a major New York demonstration last spring, U.S. intelligence officials told Congress in classified testimony released yesterday.

However, both the CIA and the FBI officers said their agencies could find no evidence that the efforts had significantly influenced either U.S. policy makers or the turnout for the rally.

The July testimony before the House Intelligence Committee was among documents President Reagan cited last month as support for his charge that the Soviet Union is manipulating the U.S. freeze movement.

Committee members immediately clashed over the impact of the hearings, which looked into the Soviets' campaign of "active measures" to promote their views worldwide.

"The bottom line is that the hearings provided no evidence that the Soviets direct, manage or manipulate the nuclear freeze movement," said committee Chairman Edward P. Boland (D-Mass.).

Although testimony showed the Soviets spent vast amounts of time and money on forged documents, planted agents and other active measures to try to influence events, Boland said, the FBI had testified that the efforts "have had, at best, minimal impact on U.S. decision makers."

Rep. C.W. (Bill) Young (R-Fla.), a conservative committee member, told a news conference he did not agree that the hearings produced no evidence of Soviet involvement.

He said he had "provoked, pushed and irritated" the committee into holding the hearings because the Soviet active-measures campaign "is growing and it's essential that the American people know about it."

All sides agreed that the Soviet Union, through its KGB intelligence agency, tries to infiltrate many groups worldwide and to influence their growth and direction. They differed over the success of those efforts and over the way U.S. citizens should respond.

"We were well aware that the peace movement in Europe did have a very native and genuine spawning," testified John McMahon, deputy CIA intelligence director, on July 13. "Yet the Soviets were able to capitalize on that and drive it much further than what the Europeans expected."

Edward J. O'Malley, assistant director of intelligence for the FBI, testified that the U.S. Communist Party, the U.S. Peace Council and the World Peace Council, which he called Soviet front groups, "were actively involved in the planning and implementation of the June 12 demonstration" in New York, which drew 500,000 people. But, he added, "I would not attribute the large turnout at this demonstration to the efforts" of those groups.

Jerry G. Berman, legislative counsel of the American Civil Liberties Union, said it was "irresponsible" of Reagan to charge Soviet manipulation of the freeze movement "when his own FBI could have told him there was no evidence to substantiate those charges."

Appearing with Young was former KGB major Stanislav Levchenko, who defected to the United States in 1979 after years of work in Japan.

The hearing testimony, much of it from Levchenko, revealed "absolutely incredible" things about KGB work, he said, and "if the people know about it, it will prevent the Soviets from infiltrating quite healthy organizations."