State Department officials asserted yesterday that U.S. security gurantees given to Israel this week are only "political reassurances" demanded by Israel and do not commit the United States to any specific military actions to protect the Jewish state.

These assertions-which contradict Israeli and Egyptian interpretations that the new assurances draw the United States deeper military into the Middle East-were made as the Senate's Democratic and Republican leaders complained publicly that they had never been told about the secret negotiations on the assurances.

"I think it was a tragic mistake that we were not told in advance," said Sen. Howard H. Baker Jr. (R-Tenn). But Baker added that Congress would not now object to the U.S.-Israeli memorandum of agreement that was signed Monday two hours after President Carter, Israeli Prime Minister Menachem Begin and Egyptian President Anwar Sadat signed the Egyptian-Israeli peace treaty.

"Congress should have been informed during the discussions," Sen. Robert C. Byrd (D.W.Va) said. And Sen. Barry Goldwater (R-Ariz.) added: "It's time we are told what's going on when Carter, Begin and Sadat get together over a cup of tea and start swapping."

The language of the memorandum assures Israel that the United States "will take appropriate measures to promote full observance of the treaty of peace" and "will provide support it deems appropriate for proper actions taken by Isreal in response" to violations of the treaty.

Moreover, the memorandum commits the United States to consider for mally and urgently "such measures as the strengthening of the United States presence in the area, the providing of emergency supplies to Israel, and the exercise of maritime rights in order to put an end to the violation."

Despite repeated questions, the State Department official who appeared at the daily department press briefing yesterday refused to say if a naval blockade or other action undertaken by any other Arb country against Israel would trigger U.S. action to restore peace. His most forthright statement was that the memorandum "could relate to situations involving parties other than" Egypt and Israel.

State Department spokesman Hodding Carter introduced the official and required that reporters attending the briefing not identify the official because the official "wants it that way."

As described by the official, the Carter administration provided the new assurances grudgingly and warily after Israeli negotiators stressed the "considerable importance" they attached to the memorandum's role in underpinning the treaty. President Carter discussed the memorandum on his Middle East trip this month, which cleared the way for the signing of the treaty.

The memorandum "is obviously a matter of very substantial political reassurance to Israel," said the official, who added that each of the three countries had to take its domestic constitutency into account in signing the treaty. Calling the security assurances "guidelines" to possible future U.S. action that he said were subject to "qualifiers and limiting phrases," the official said the memorandum "has a very important diplomatic and political significance to Israel."

Egypt has protested that the memorandum of agreement is "directed against Egypt" and calls for an increased U.S. military presence in the Middle East "for reasons agreed between Israel and the United States."

Hodding Carter described the Egyptian protest as "a disagreement being expressed between friends," and predicted that the memorandum would not have adverse long-term effects on U.S. relations with other Arab countries.

A State Department official said that Egypt had turned down an offer for a similar bilateral memorandum of understanding because "Sadat said they didn't need it."

The other unidentifiable State Department official said that the Egyptian protest had no legal effect on the memorandum, even though the document requires, that both countries be consulted before considering action. The official said that there should be other means for consulting Egypt if necessary.