American allies Thailand and France announced today that they would support a Security Council resolution condemning Israeli practices against civilians in southern Lebanon, providing the votes needed to force a U.S. veto of the Lebanese draft Tuesday.

U.S. officials had made clear their opposition to the text and lobbied intensively to prevent it from getting the nine-vote majority required under the rules of the 15-nation council.

Diplomats said the "hardball" lobbying effort by both sides extended to the capitals of the four council members -- France, Thailand, Peru, and Trinidad and Tobago -- whose votes remained uncertain at the end of last week.

Lebanese officials, backed by the Syrians, said they had refused to modify the wording of the resolution and vowed to put it to a vote whether or not they had a majority.

It was not until the statements in the council debate this afternoon -- first by Thailand's Birabhongse Kasemsri and then by Claude de Kemoularia of France -- that it became certain that the Lebanese could count on the two additional votes they needed.

The council vote, and with it the American veto, was scheduled for Tuesday morning, after more than 30 countries voiced support for the Lebanese in a debate that continued into the night.

The need to veto the resolution raised concern in Washington because, according to American officials, at least three specific threats have been made against the lives of Americans in Lebanon in the event that the U.S. blocks its passage.

In response to the threats, the United Nations has withdrawn 36 Americans serving with its peace forces in the Beirut area and in southern Lebanon.

American representative Jeane J. Kirkpatrick, in a speech to the council last week, cautioned that the threat to Americans also constitutes an attempt at blackmail that could cripple functioning of the council. She called on council members to repudiate the threats.

At the State Department, spokesman Ed Djerejian said the United States deplores the violence and destruction in southern Lebanon, but he declined to cast blame at either Israeli or Lebanese armies.

The Lebanese sought council action to satisfy pressures from the Shiite Moslem community for international response to Israel's hard-line policy against Shiite villagers in the south. The Israelis maintained that their actions have been purely defensive, designed to prevent terror attacks while their occupation troops withdraw.

But western diplomats said the timing of the debate was also dictated by Syria's desire to provoke an American veto and to embarrass President Hosni Mubarak of Egypt during his Washington visit.

They noted that Egypt would be obliged to vote publicly against Israel in the council at a time that Mubarak is appealing to the U.S. administration and Congress for additional financial support and backing for his peace initiative. The Egyptian proposal, diplomats noted, would bypass Syrian participation in Middle East negotiations, and the Syrians wished to demonstrate that they could not be taken for granted.

The resolution, in addition to condemning "the Israeli practices and measures against the civilian population in southern Lebanon," also demands that Israel lift its restrictions on the civilian population in the area.

It reaffirms an earlier demand for immediate and total withdrawal of Israeli troops and would establish a U.N. fact-finding mission on the measures taken against the civilian population.