Three Harvard professors are among 18 disarmament advocates who called in a statement released Sunday for a worldwide reduction in nuclear weapons.

Harvey Brooks, McKay Professor of Applied Physics, Abram J. Chayes '43, professor of Law and George B. Kistiakowsky, Lawrence Professor of Chemistry, Emeritus, are members of the Canadian-American Pugwash Group that issued the declaration asking nations to ban all underground testing.

The Pugwash Group, an unofficial international organization, is composed of scientists and specialists in international law.

Kistiakowsky said yesterday he signed the statement because it "correctly represents a situation that is very threatening."

"Past efforts to slow down or terminate the arms race were not successful, not-withstanding Mr. Nixon's and Mr. Brezhnev's SALT devices to cover up the arms race with trivial issues," he said.

Kistiakowsky, a physicist who worked at Los Alamos, N.M., in the 1940s, developing the atomic bomb, called the recent Moscow summit talks a "complete and total fraud."

He said it was a "matter of conscience to come out with a public statement. I had to raise my voice when I saw Mr. Nixon building an image of peace while jeopardizing the whole world."

Kistiakowsky also said the proposed Senate resolution limiting the size of underground explosions to 150 kilotons is "meaningless" because 99 per cent of the tests the military wants could be carried out under this level.