Syria refused today to allow an armored rescue convoy of American, French and Italian troops into the Syrian-controlled mountains of eastern Lebanon where more than 100 people are believed to be stranded in the worst snowstorm there in memory.

The Syrian government's refusal may have been based on suspicions about the intent of the multinational ground units--perhaps worried about possible spying or being seen by Arab rejectionists as too friendly to the western forces--because it earlier had given permission to a multinational air rescue operation and in other ways was cooperating in the unusual international effort to save the stranded victims.

But after U.S. Marine choppers began icing over during two attempts to conduct reconnaissance above the stricken area, air operations had to be suspended this morning. The multinational force's armored convoy then waited four hours in the foothills outside Beirut as diplomats sought permission from the Syrians to allow them to attempt to move the convoy into the mountains.

The Syrians finally replied that they would permit only Lebanese Army ground convoys to enter areas under their control, according to U.S. Marine spokesman Capt. Dale Dye. He said he understood that the Syrians gave no reason for denying entry to the multinational force.

Marine commander Col. James Mead said he had learned that roads leading into the area were impassable so that the diplomatic flap may in the end have been entirely "academic."

At least 50 persons have frozen to death in the snowbound Dahr al Baydar mountain peak on the Beirut-Damascus highway about 25 miles east of Beirut. One of the victims was a Japanese, whom the Lebanese Army identified as a diplomat, but the news agency Reuter reported that Japanese sources in Beirut said he was Kazuo Togo, a businessman.

More than 300 people had been trapped in cars but an effort by the Lebanese Army, civil defense units and other teams managed to rescue about 150 of them during operations Sunday and today.

The Lebanese say that February is always the cruelest month in Lebanon, but the severe weather this year is extreme. Indeed, talk of the weather has temporarily replaced the usual talk of the town--of car bombs, troop withdrawal negotiations and war.

The silver lining in this snowstorm that hit on Sunday has been the unusual way the various nations and forces in Lebanon, at loggerheads and in violent conflict at other times, have been cooperating in the face of this natural disaster, the Syrian rejection of the multinational force convoy notwithstanding.

American and Israeli commanders whose relations have been strained at best in the past were on the line today exchanging information about road conditions in the mountains.

Syrians and Israelis who have strictly guarded their positions against encroachment by other military forces lowered barriers to allow the Lebanese Army through.

A Norwegian diplomat who returned here today hoarse but well talked of the relief of being picked up by a Syrian military snowmobile after being trapped in the mountains on an impassable road for nine hours.

The Syrians took him and about 15 Lebanese who had also been stranded in cars on the road off to a well-heated military outpost where they fed them and administered first aid. When weather conditions improved slightly, the Syrians piled them into snowmobiles and took them down the mountains where they were turned over to the Lebanese Army.

"The Syrians were really very professional in dealing with it," said the diplomat.

But the Syrians balked at the possibility of having the massive multinational force convoy enter the area it controlled. The Marines had been prepared to send 110 troopers in nine amphibious tracked personnel carriers, known as amtraks, two trucks and a refueling vehicle. The Italian contingent included 22 soldiers in one Leopard tank with a snowplow, one bulldozer, and three jeeps. The French had a 20-man unit with two bulldozers and two trucks.

A spokesman said the Marines intend to try Tuesday to mount an air rescue operation in the Syrian-controlled area. He said Col. Mead intended to conduct reconnaissance operations himself Tuesday morning.

If the air rescue effort is not feasible, the spokesman said the Marines would again seek permission of the Syrians to send in a ground convoy. He also said Marines might be sent north into a Christian-militia controlled area of Lebanon's central mountains to try to rescue people trapped there by the blizzard.