Iraqi armored forces charged out of occupied Kuwait and battled allied forces in Saudi Arabia Wednesday in the heaviest ground fighting of the Persian Gulf war, leaving between eight and 10 U.S. Marines dead. The Pentagon said the enemy was driven back and suffered heavy losses.

The fighting on the 14th day of the war erupted as the United States and the Soviet Union offered Iraq a cease-fire in exchange for an "unequivocal commitment" to leave Kuwait and President Bush restated his belief in an allied victory over the forces of Saddam Hussein.A column of Iraqi tanks and other armored vehicles, which had been massing inside Kuwait near the Saudi border, rumbled over the frontier about midnight local time (2 p.m. MST Tuesday) toward the Saudi oil town of Khafji and were met by allied ground forces, including U.S. Marines, according to staff officers of the 1st Marine Division.

The Iraqi forces were driven back in at least nine hours of heavy ground and air fighting in which between eight and 10 U.S. Marines were killed and two American armored vehicles were destroyed, the officers said. Marine Lt. Col. Cliff Myers described the battle as "hellacious."

The Marine staff officers said at least 20 Iraqi T-55 tanks and armored vehicles were destroyed and 13 enemy soldiers were captured. Troops from the allied Persian Gulf nation of Qatar also took part in the battle, destroying two Iraqi tanks and taking 10 enemy prisoners.

In Washington, a Pentagon official said about one-third of the 1,500-man Iraq force was injured or "otherwise incapacitated" and suffered heavy equipment losses. The size of the allied force was not disclosed.

"We successfully repelled the probing attack," a Pentagon official said, but he emphasized that it would be too strong to say the Iraqis were "defeated."

A Pentagon official called Iraq's incursion a "probing attack," saying it would be an "overstatement" to call it a major offensive signaling the start of a ground war. "It's not really designed to capture ground," he said, but to "feel the enemy line out."

Meanwhile, a total of about 90 Iraqi planes had reached Iran as of Tuesday, Pentagon officials said but repeated their belief that the unexplained exodus did not pose a threat.

In Washington, Secretary of State James Baker and Soviet Foreign Minister Alexander Bessmertnykh, in a statement following three days of talks, said Iraq could have a cease-fire if it made an "unequivocal commitment to withdraw from Kuwait" in compliance with U.N. Security Council resolutions.

"The ministers continue to believe that a cessation of hostilities would be possible if Iraq would make an unequivocal commitment to withdraw from Kuwait," the statement said. "They also believe that such a commitment must be backed by immediate, concrete steps."

Asked if Iraq could gain a cease-fire by simply pledging to leave Kuwait, which it invaded Aug. 2, a senior administration official said, "No. They have to leave Kuwait."

But the official who asked not to be identified hinted that Saddam could stay in power after the war, saying, "Saddam as a person is not an object to this operation."

Speculation surfaced as to whether the statement was a new overture to Saddam and a possible shift of U.S. policy. But White House spokesman Marlin Fitzwater said Tuesday night there had been no shift.

In other fighting Wednesday, Lynx helicopters from British destroyers in the northern Persian Gulf attacked and sank three Iraqi patrol boats, the British Broadcasting Corp. reported. Five Iraqi boats were sunk Tuesday by U.S. Intruder bombers and the Lynx helicopters.

Iraq said Wednesday it shot down three allied warplanes during overnight raids. But Iraqi radio, monitored in Cairo Egypt, made no further mention of a report Tuesday that a captured allied airman had been killed during air raids in Baghdad. Iraq Tuesday did not give the nationality of the airman.

U.S. and British officials had no immediate confirmation of the Iraqi report.

In other updates Tuesday, Pentagon officials said the number of allied air sorties was up to more than 27,000, including 2,600 in the past day.

Officials said 25 allied aircraft have been lost in the war - including 16 U.S. aircraft. Seventeen U.S. airmen were missing and two confirmed killed.

The bombing runs have begun to have an impact on supply lines to Iraqi troops and their stockpiles, military officials said.

The 20- by 60-mile oil slick continued to creep southeast through the Persian Gulf, but military officials said the oil had stopped flowing from an offshore Kuwaiti terminal and a fire at the pipeline had burned itself out.