U.S. delegate Max M. Kampelman delivered a blistering attack on the Soviet Union's human rights record today at a plenary session of the European conference on European security.

Kampelman's speech, which drew bitter responses from East Bloc delegates, came only three days after the United States joined the Soviet Union and 32 of the other 33 delegations in provisionally approving agreements that will continue the detente process begun at Helsinki in 1975.

Kampelman said later he did not believe his speech--made at a closed-door session--would jeopardize last week's draft accords, which represent the first East-West agreement of note since the Soviet invasion of Afghanistan in 1979. Western and eastern diplomats agreed that the accords stand. Adjournment of the conference is being delayed, however, pending disposition of Malta's demand that the final document include a call for a conference on Mediterranean security.

Talking to reporters after the meeting, Kampelman conceded that his explicit references to human rights violations by the Soviet Union, Poland, Czechoslovakia and East Germany were "a warning against euphoria" over the substance of the Madrid concluding document.

The U.S. delegate rejected suggestions that his speech was aimed more at the U.S. congressional commission on the Helsinki process, before which he is scheduled to testify Thursday, than at the assembled delegations. Nevertheless, the speech seemed to be addressed to critics who might accuse the West of "selling out" at Madrid. Kampelman asked rhetorically: "Why do we enter into an agreement at a time when repression of human beings in the Soviet Union is greater than at any time since the Helsinki accords were signed in 1975?"

He answered: "It is because the pursuit of peace is too vital, the need for understanding too indispensable, the importance of the Helsinki accords too great to permit us to be discouraged by the task or the obstacles we face."

Responses to Kampelman by the Soviet, Polish, East German and Czechoslovak spokesmen labeled the speech variously as insulting, confrontational, fallacious and unfounded slander. Soviet delegate Andrei Kondrashev tried to silence Kampelman on a point of order, but was overruled by the chair.

According to a U.S. delegation spokesman who attended the meeting, Kondrashev told delegates that Kampelman's speech was "the most unworthy ever made" at the Madrid conference. He accused Kampelman of casting aspersions on the spirit of the Helsinki Final Act.

Speaking later to reporters, Kampelman said his speech was consistent with "what we've been saying here for the past two years and 10 months the duration of the Madrid conference ." He said the language he had used was "accurate, not strong."

In attacking Soviet Bloc violations of the Helsinki undertakings, Kampelman said, "We cannot permit an agreement on words to obfuscate unpleasant realities."

He assailed the invasion of Afghanistan as "an affront to the peace we in Helsinki professed to pursue." He described Soviet barriers against Jewish emigration as "a tragic violation of the Helsinki accords," and he called Moscow's harassment of human rights activists one part of "an indefensible double standard."

Kampelman also attacked the treatment of pacifists and others who support disarmament in East Germany and Czechoslovakia, mentioned the arrest of Seventh Day Adventists in the Soviet Union and referred to the "internment and imprisonment of thousands of persons who declare and champion human rights in Poland."

Kampelman told the plenary session that the provisional Madrid accords go beyond the Helsinki final act and are noteworthy because they include provisions ranging from religious rights and trade union rights to the rights of the so-called Helsinki monitors who work for human rights in the East Bloc. He said the Madrid mandate for a European disarmament conference next year is a "significant step toward strengthening security."

Kampelman said the U.S. delegation and others will continue to oppose the amendments proposed by Malta, which under the consensus rules of the Helsinki process can prolong the conference by refusing to agree. He told reporters he expected the Maltese filibustering to continue for a few more days.

Diplomats said that a formal closing ceremony probably will be held in the second week in September, with foreign ministers of all the participating states--the United States, Canada and all European countries except Albania--in attendance.