Presidential emissary Clark Clifford said yesterday the United States must make unmistakably clear to the Soviet Union that any Soviet attempt to take control of the Persian Gulf and its oil would be an act of war.

Testifying before the Senate Foreign Relations Committee, Clifford stood by his controversial statement in India earlier this year that the United States would construe further Soviet actions like the invasion of Afghanistan as "an act of war."

At the time, the Carter administration tried to tone down the implications of Clifford's remark by having Secretary of State Cyrus R. Vance say he would not have stated U.S. policy in such dramatic terms.

However, Clifford yesterday said that, after his return from India, he had talked with President Carter and Vance and was satisfied that his statement was in accord with the warning issued by Carter in his January speech on Afghanistan.

At the time, the president said any attempt by an outside force to gain control of the Persian Gulf would be regarded as an assault on U.S. vital interests and would be repelled by any means necessary, including military force.

Clifford, a former defense secretary and adviser to Democratic presidents since the Truman administration, was sent to New Delhi by Carter for consultations with Indian Prime Minister Indira Ghandi in the wake of the Afghanistan invasion. In regard to his statements there, he told the Senate committee:

"When I was in India, I wanted to make sure that the message had gotten over. The Soviets monitored every word that was said in India, and I said I though the president had stated it extraordinarily well.

"My only innterpretation of that was, if the Soviets moved into the Persian Gulf with the idea of taking over that area of the world, we would have to construe it as an act of war. And I believe that is what we have to do.

"Perhaps more diplomatic terminology could have been used," he added. "But in this area, I felt diplomacy is not so much what's needed as specificity."

Elsewhere on Capitol Hill yesterday, Vance refused to discuss with Congress details of why Carter disavowed a U.S. vote for a U.N. resolution criticizing Israel. The president said the March 1 vote had been a mistake, and Vance subsequently took responsibility for "the failure in communications" that led to the controversial turnabout.

During testimony on the foreign aid program before a House Appropriations subcommittee, Vance was asked for an explanation. But he replied: "I am not going to go into details of executive communications between the president and myself and between myself and others."

The secretary is scheduled to testify about the U.N. vote before the Senate Foreign Relations Committee Thursday. However, State Department officials made clear last week that he will not discuss matters the administration regards as falling in "the highest category of executive privilege.

Clifford, in his testimony, likened the situation in Southwest Asia to Europe in the 1930s, and said failure to stand up to the Soviets could have the same consequences for world peace as did the unwillingness of the European democracies to counter Nazi Germany's aggresiveness.

He lauded Carter's tough responses to the Afghanistan crisis and suggested a seven-point U.S. program for the region.

He listed its main points as detering Soviet adventurism in the region, ensuring U.S. and western access to the Persian Gulf and its oil, persuading the Soviets to withdraw from Afghanistan, strengthening U.S. alliances with the North Atlantic Treaty Organization, Japan and the ANZUS pact with Australia and New Zealand, adopting an energy policy that would lessen U.S. dependence on imported oil, strengthening the countries of the region with special emphasis on China, India and Pakistan and seeking ways to maintain the basic framework of relations with the Soviet Union.

In questioning Clifford, a member of committee members expressed concern about what they called "the business-as-usual" attitude of U.S. allies, particularly in Western Europe, toward the Soviet Union, and their unwillingness to support many of Carter's get-tough approaches.

Clifford, recalling his comparison with European attitudes about dealing with Hitler in the 1930s, said of the Europeans: "I believe they're engaged in a policy of wishful thinking, and they hope it'll all go away . . . I would hope there would be a better understanding of the price we will have to pay if we do not stand up to the Soviet Union."