Secretary of State Cyrus Vance moved today to reassure Israel on the U.S. position toward the terms a peace settlement in the Middle East and on continuing deliveries of American arms.

Israeli officials have recently expressed nervousness that the United States may moved to impose a settlement between Israel and the Arab states and that new U.S. arms-transfer policies may cut off advanced arms Israel wants.

While Vance sought to assuage such feelings today, sources close to the Vance mission suggest privately that the Israeli anxieties are not altogether misplaced and that Israel could be in for a more difficult time under the Carter administration.

In this view, President Carter is personally eager for a Middle East settlement, and a settlement is likely to invole a return to Israel's pre-1967 borders, something it has steadfastly resisted.

The United States, in this view, is committed to secure borders for Israel and to recognition of Israel by the Palestinians, but also insistent that any change in borders be mutually acceptably.

If the Arabs are seen as becoming more flexible and the Israelis as more obstinate, it could cause a confrontation with the new President.

"We have made it very clear that we have a special relationship with Israel," Vance said after talks here with Israeli Foreign Minister Yigal Allon. "We are committed to the security of Israel and we will make sure Israel has the defense material necessary to protect that security - including the advanced technology required."

Allon, who also met with reporters after the private talks in the U.S. embassy here, said: "I have been given to understand that the United States does not intend to come out with a [peace] plan of its own. Agreement should be reached by the parties on their own, and the United States will facilitate this through its good offices."

Vance also said that "no such thing" as an imposed settlement "is intended in any way."

"If there is to be a just and lasting peace in the Middle East, then it must be determined by the parties in the negotiations themselves," Vance said.

He added, however, that the United States wants to help "facilitate that process" and may have some "suggestions of its own."

Today's meeting between Vance and Allon was another in a series of talks between top U.S. officials and leading Middle Eastern officials.

Vance reportedly brief Allon on President Carter's talks with Syrian President Hafex Assad in Geneva Monday and attempted to offer some further explanation of what Carter meant by his public references to a "homeland" for the Palestinians, another source of vagueness that worries Israel.

The meeting here today followed reports that the Syrian president had outlined a new plan put forward by three Arab states and the Palestine Liberation Organization that reportedly calls for setting up an independent Palestinian state in the Israeli-occupied West Bank of Jordan and the Gaza Strip.

Under questioning today however, Vance said, "There have been no specific proposals made by either side at this time." He said the United States is still trying to get the general views of the parties.

Israeli's concern over the flow of arms from the United States grows out of reports that a new proposal before Carter would exlude Israel from the preferred status enjoyed by NATO countries and Japan.

Vance said Washington will continue to "make sure Israel has the defense articles necessary" to preserve its security, but the question has always rested ultimately on how Washington defines what is necessary for that "security." Under a new administration, that assessment could change.