President Carter said yesterday that he has been given assurances that a controversial new Jewish facility in the Israeli-occupied West Bank of Jordan is not a civilian settlement.

Carter sent a message to Israeli Prime Minister Menachem Begin last week complaining about the apparent establishment of what he called an "illegal" settlement at Shiloh, north of Jerusalem. He pointedly noted that Begin had given him a commitment that no new cilivian settlements would be authorized in occupied territories.

Asked about the facility at Shiloh at his news conference yesterday, Carter said, "I think the Israeli government has not authorized the Shiloh settlement other than as an archeological exploration project."

He said that he had not heard directly from Begin about the matter, but he said, "I have had information that this is the policy of the Israeli government, that this is not an authorized settlement."

The Geneva Convention forbids establishment of civilian settlements in occupied territories, and the United States has for several years characterized the dozens of Israeli civilian settlements as illegal and an obstacle to peace.

Carter repeated this position yesterday and said that Begin and Israeli Foreign Minister Moshe Dayan had both given him a "commitment" that "any increase in settlers would be an expansion of existing settlements as much as possible within the aegis of the military."

Members of Gush Emunim, a nationalistic Jewish movement that has attempted to establish unauthorized settlements in the past laid a corner stone for a new village at Shiloh last week. The Israeli military government, which administers the occupied territories, said the ceremony was not authorized but did not block it.

About two dozen members of the movement are camping at Shiloh, the traditional site where, in biblical times, the sacred Ark of the Covenant was kept before the kingdom of Israel was established.

Carter's message to Begin last week, apparently delivered by U.S. Ambassador Samuel W. Lewis, said:

"I deeply regret the effort to establish another illegal settlement on the West Bank of Shiloh. However I am confident that Prime Minister Begin will honor the commitment personally made to me and thus will not permit this settlement to go forward."

Israeli officials refused yesterday to comment on the letter but there were reports in Jerusalem that Begin was preparing a reply.

In other questions dealing with the Middle East, Carter said he expected to decide by the end of the week whether to supply weapons to Egypt, and he reiterated his position that he would not prepare his own proposed map of Middle East peace borders.

President Anwar Sadat, who is scheduled to meet here with Carter this weekend, has asked the United States to supply Egypt with F5E jet fighters. The United States so far has supplied Egypt only with non-lethal equipment, including cargo planes and electronics gear.

Carter said yesterday that the National Security Council will make a report to him early this week containing recommendations from the State Department, Pentagon and the national security adviser on what types of material the United States should supply to Egypt.

Carter said he will decide later this week what to recommend to Congress, which would then have 50 days in which to veto the proposal.

Asked whether he had a plan for the final borders he would like to see for Israel as a result of a peace agreement, Carter said, "I have never tried to put forward in my own mind or to any of the Mideastern leaders a map saying this is where the lines should be drawn."