WASHINGTON, Oct. 23, 1983 (UPI) - President Reagan, denouncing the ''bestial nature'' of terrorist bombings in Lebanon that killed scores of American and French troops, vowed Sunday foes of the peace-keeping force cannot ''drive us out.''
''I know there are no words that can express our sorrow and grief for the loss of those splendid young men ... no words that can ease the grief of the families of those young men,'' Reagan said at the White House.
The president, who hastily returned to Washington from a weekend golf outing in Georgia, immediately began meeting with top aides on the events of ''this tragic weekend.''
Reagan called the bombing a ''despicable act.''
Deputy White House press secretary Larry Speakes said the casualty figure as of 6:30 a.m. EDT was 76 Marines dead and 112 injured.
''These are changing figures,'' he stressed, reporting the French deaths at 18.
Speakes said U.S. officials ''do have, as we have had all along, some suspicions'' about who is responsible for the attack, ''But we're not ready to go into who we may suspect.''
One thread of suspicion focuses on an Iranian-backed group believed responsible for the April 18 attack on the American Embassy in Beirut, officials said.
Pentagon spokesman Air Force Lt. Col. Mark Foutch said preliminary plans called for evacuating injured Americans to either Landstuhl Army Hospital or Weisbaden Air Force Hospital in Germany.
Foutch said it would be several hours before authorities could begin releasing names of those killed. He cited the time necessary to confirm the victims' identities and notify relatives.
Reagan, standing in rain on the White House lawn, was accompanied by Secretary of State George Shultz and Robert McFarlane, his new national security adviser.
Also attending the session at the ''situation room'' were Vice President George Bush, Defense Secretary Caspar Weinberger, deputy CIA director John Mahon; Gen. John Vessey, chairman of the Joint Chiefs of Staff; Gen. Paul Kelley, commandant of the Marine Corps; and top Reagan aides, including chief of staff James Baker, deputy chief Michael Deaver and counselor Edwin Meese.
Speakes said he expected congressional leaders to be briefed by National Security Council aides on developments and decisions after the meeting.
''I would not anticipate any major announcement,'' Speakes told reporters.
Reagan, holding an umbrella as he faced the press corps, refused to answer questions but delivered a brief statement, speaking without notes.
''There are no words to properly express our outrage and I think the outrage of all Americans at the despicable act,'' he said.
''I think we all should recognize that these deeds make so evident the bestial nature of those who would assume power if they could have their way and drive us out of that area.
''But we must be more determined than ever that they cannot take over that vital and strategic area or for that matter any other part of the earth,'' Reagan said.
Reagan shook his head ''no'' when a reporter asked if he knew who was responsible for the attack, then hurried into the White House.
The president, awakened within hours of the attack, cut short a weekend holiday to return to Washington. Air Force One left Bush Field near Augusta in a driving early morning rain and arrived at Andrews Air Force base outside Washington about 8:20 a.m. EDT.
Col. Timothy Geraghty, the commander of the Marines guarding the Beirut airport, told a press conference more than 70 Marines were known dead, more than 100 wounded and many others missing in the rubble of the battalion landing headquarters.
Marines in nearby companies were wounded when the explosion -- caused by a truck loaded with an estimated ton of explosives -- knocked soldiers out of their bunks and sent shards of glass and boulders flying through the area, Marine officials said.
State-run Beirut Radio reported 120 Americans and 19 French soldiers were killed.
Reagan called Marine Corps Commandant Kelley to express his ''deep personal sense of loss over the sacrifice of the Marines,'' White House officials said.
White House spokesman Peter Roussel said the president was informed by McFarlane of the bombing at 2:27 a.m. EDT -- about 2 hours after it occurred.
The latest casualties are bound to increase pressure on Reagan, who signed a congressional resolution Oct. 12 authorizing American troops to remain in Lebanon for 18 months without further congressional approval.
Last week, reacting to sniper attacks that had killed half a dozen Marines, Reagan declared, ''We're going to keep on doing what we have been doing'' in Lebanon.
''We know there are hazards there,'' he said. ''And no one can feel more deeply about the loss of life and the wounding of some of our men there.
''We knew it was a hazardous undertaking when we joined in the multinational force, but our objective remains the same. We have made great progress there.''
''As long as there's a possibility of making the overall peace plan work,'' Reagan said, ''we're going to stay there.''
Reagan's weekend already had been disturbed by a hostage-taking incident while the president and two Cabinet members were playing on the exclusive Augusta National Golf course. The incident ended with the surrender of the gunman and no casualties. Reagan was never in danger, a White House spokesman said.