The U.S. aid program and alliance relationship with Pakistan, where the Carter administration had planned to draw the line in Southwest Asia against the Soviet Union, was all but dead yesterday following public statements and private irritation in Washington and Islamabad.

"The Pakistani government has indicated that it is not interested in the assistance we proposed," said State Department spokesman Hodding Carter. Saying that the administration has no plans at this time to go forward with the offered $400 million U.S. aid program and reaffirmation of U.S. security guarantees, Carter declared that "it is obviously up to Pakistan to determine its own needs and priorities."

His statement followed declarations by top Pakistani officials in Islamabad that the U.S. package remains unacceptable five weeks after a special mission, headed by presidential assistant Zbigniew Brzezinski and Deputy Secretary of State Warren Christopher, went to Pakistan to present it.

Pakistan's rejection of the aid program, as originally presented, has also been conveyed to the United States several times in recent weeks through diplomatic channels, according to Washington officials.

Washington Post correspondent Stuart Auerbach, reporting from New Delhi, said Pakistan continues to welcome U.S. economic assistance and would like new U.S. arrangements on a basis of lower visibility.

But Pakistani diplomatic sources quoted by Auerbach said the proposed U.S. program was too small and too conspicuous, with the result that Pakistan is "being accused as a surrogate of the United States acting against India and the Soviet Union."

The high-profile U.S. offer to aid and defend a visibly threatened Pakistan emerged from President Carter's public statements and quick-response administration policymaking following the Soviet invasion of Afghanistan Dec. 27.

The spurning of this offer as inappropriate and poorly tendered is another blow to U.S. diplomacy, now under fire from several directions for mistakes and inadequacies.

The formal stance of the two nations has been constant since the Brzezinski mission -- on the U.S. side, that its offer of a $400 million package is on the table, awaiting Pakistani approval; and on the Pakistani side, that this offer is unacceptable but that elements of it are not ruled out.

What has changed in recent days is the tone of the statements on both sides, indicating growing impatience and irritation, and leading to a sharply diminished expectation that a way will be found for the program to go ahead.

It is increasingly clear, according to State Department officials, that the "package" plan will not go ahead, and that Pakistan is not interested in a security relationship with the United States under existing circumstances.

As originally presented, the package deal for Pakistan had three elements -- a reaffirmation of U.S. security commitments to aid that country against Soviet aggression, $200 million over two years in military sales loans, and $200 million over two years in economic aid.

To make the package possible, the administration was prepared to ask Congress for an exception to nuclear antiproliferation laws, which prohibit military and economic aid to Pakistan because it is believed to be seeking to make nuclear weapons.

Pakistani officials made it clear in discussions with Brzezinski and Christopher, according to sources on both sides of the diplomatic table, that Pakistan hoped for a reaffirmation of the U.S. security commitment despite doubts about the aid programs. The U.S. position was that the commitment could not go forward without the other parts of the planned package.

With U.S. approval and, in some cases, U.S. assistance, Pakistan has been seeking aid from a variety of other Islamic and European nations. Saudi Arabia is negotiating with Pakistan to provide up to $750 million to help in a military buildup, official sources told Washington Post staff writer George Wilson.

During a visit to Islamabad this week, a special envoy from Japan announced an economic aid program of $130 million, double the previous level. But aid commitments from European nations so far have been modest or nonexistent. Pakistani officials are reported to be disappointed by a seeming decline of interest on the part of donor nations.

The proposed U.S. aid program of $400 million over two years was devised at the turn of the year, at an awkward point in the U.S. budgetary cycle. The tight-fisted Office of Management and Budget reportedly had a major role in establishing the figures, which leaked to the press before Pakistan was informed. President Mohammed Zia ul-Haq immediately denounced the sum as "peanuts," but the United States insisted that it would not be increased.

The diminished prospects of the U.S. aid program for Pakistan will make it more difficult for American diplomats to ask other countries to provide assistance to Pakistan, State Department sources said. The lack of rapport between Washington and Islamabad also weakens the significance and impact of U.S. security commitments to that nation, officials said.