The United States vetoed a Security Council resolution today condemning the "appalling acts of sacrilege" in Jerusalem nine days ago when two worshipers in the Dome of the Rock mosque were killed in a burst of gunfire. An American-born Israeli soldier was arrested in connection with the shooting.

U.S. Ambassador Jeane J. Kirkpatrick stood alone in opposing the draft, which was backed by the other 14 council members.

She explained the American stand--the third U.S. veto on Israel's behalf this year--by saying that the resolution implied that Israeli authorities were responsible for "this terrible event." Its adoption, she added, would have increased the bitter divisions in the region that "would make new acts of violence more likely to take place."

But the unstated American motive, diplomats said, was a hint from Israeli officials that an abstention, which would have permitted the resolution to pass, would increase domestic pressures on Israel just five days before it is scheduled to return the last chunk of the Sinai Peninsula to Egypt. The extent of American diplomatic support has become a prime issue in Israel.

In an attempt to soothe Arab feelings, Kirkpatrick strongly condemned the "senseless act of violence at one of Islam's most sacred shrines," and expressed her condolences to all who have suffered. A number of Moslem worshipers were wounded in the melee.

The incident took place on April 11, when a gunman allegedly fired his M16 rifle into the crowd on the sacred Temple Mount. A 37-year-old Israeli Army reservist identified as Alan Harry Goodman was arrested immediately afterward.

Despite Kirkpatrick's affirmation that the veto does not alter Washington's policy that the final status of Jerusalem can only be determined through negotiation, Arab and Soviet representatives took the opportunity to denounce the vote as fresh evidence of a "watershed" in American bias in favor of Israel.

Israeli Ambassador Yehuda Blum denounced the resolution, just before the vote, for seeking to single out Israel for a crime it did not commit, "the crime of a single individual acting on his own."

Blum called the April 11 attack "a despicable act of sacrilege," and noted that Israel had acted swiftly and effectively to arraign the person responsible.

The issue was brought to the council by King Hassan II of Morocco, on behalf of the group of 40 Islamic nations. But Egypt, for reasons similar to those of the United States, did not join in the move.

The Arab diplomatic offensive against the Camp David process continued at the United Nations just an hour after the council vote with the reconvening of a 20-month-old special session of the General Assembly devoted to the issue of Palestine.