The United States said today that it will withdraw its opposition to the admission of Vietnam to the United Nations, but it refused to agree to pay war reparations that Vietnam has sought as a step toward normalizing relations.

At the end of two days of high-level talks here between the two governments. U.S. delegation spokeman Morton Smith said that the Carter administration sees no major hurdles, from the American standpoint, to establishing full diplomatic relations with [WORD ILLEGIBLE]

At a separate briefing Vietnam's Deputy Foreign Minister Phan Hiou told reporters, however, that Hanoi still links diplomatic relations to American economic and for reconstruction and repair of war damage. Smith confirmed that Vietnam had made the same linkage during the closed talks.

Secretary of State Cyrus Vance told a press conference in Washington that the United States had made it clear that it refuses to pay any reparations. He said that the Vietnamese are demanding economic assistance as a precondition to full normalization of relations and that this is one of the major differences between the two sides.

President Carter said in March that he "would aggressively move to admit Vietnam to the United Nations and also to normalize relationships with them" if " we are convinced as a result of the negotiations and other actions on the part of the Vietnamese that they are acting in good faith."

The talks were adjourned for two weeks. The tone and content of the announcements indicated that no major progress had been made on the issues still separating the two countries, and that Vietnam is prepared for protracted and difficult bargaining if necessary.

Assistant Secretary of State Richard Holbrooke, who led the American delegation, did not appear at the American briefing. Smith sought initially to avoid discussion of the economic demands Vietnam had raised in the talks before acknowledge that the U.S. delegation had "taken note" of Vietnamese views.

On the politically sensitive issue of 2,550 U.S. servicemen still listed as missing or whose bodies are unaccounted for, the Vietnamese promised to expand their efforts to gather and provide information. One new name of an identified dead American was provided during the talks, Smith said.

"We think they have more information and that they can obtain more information, and they have indicated they will do so." Smith said in indicating that the United States is satisfied with the Vietnamese efforts and pleges.

While the United States expects "continued progress" on the missing-in-action question, he said that this no longer represents a precondition to the establishing of diplomatic relations.

"We're not setting any preconditions," Smith noted. "Continued progress on this is essential regardless of the state of our relations."

The briefings suggested that Vietnam concentrated on the economic benefits of ending 16 years of hostility between Washington and Hanoi. In addition to bringing up reconstruction aid, Phan Hien also demanded an immediate lifting of the American trade embargo against Vietnam and indicated interest in having American companies resume exploration for offshore oil deposits.

Speaking to reporters, Phan Hien listed Vietnamese economic demands as $3.25 billion the Vietnamese claim the Nixon administration promised for reconstruction; $1 billion to $1.5 billion due under another section of the 1973 peace accords and about $150 million for Vietnamese assets of the conquered South Vietnamese government under American control.

But Smith said that no fingers had been mentioned by the Vietnamese, who did not refer specifically to the Nixon administration pledge in the private talks.

The U.S. spokesman acknowledged that the decision to drop the American veto against Vietnam's U.N. membership application had not been based on anything that emerged from the two days of talks, and that it was announced here as a unilateral gesture toward the Vietnamese, "who have always considered it an obstacle."

"We believe in the university of U.N. membership," Smith said. The Ford administration cast five veotes against Hanoi's application between July 1975 and last November.

Vietnam did not offer a reciprocal gesture and was not asked by the Americans to do so, Smith said.