In Southern Lebanon, United Nations' forces moving in to take up their peacekeeping role have again come into conflict with Christian forces. The Christians fear the U.N. troops will be less effective than Israel at maintaining security. Meanwhile in Washington, Israeli Prime Minister Menachem Begin has ended his talks with President Carter with their differences over the question of a Middle East peace settlement unresolved. Mr. Begin has accused the United States of suddenly dropping its support for his peace proposals because of objections from Egypt.

SYNOPSIS: The vanguard of the United Nations force, some 200 Iranian troops, had encountered threats, but little opposition, from Lebanese Christians as they moved into the region on Wednesday. But, as they were joined by reinforcements on Thursday, there were several moments of tension -- especially near the Litani River, the northern limit of Israel's advance.

Falangist Christian militia fired over the heads of one U.N. patrol, but there were no casualties. Other groups were halted by tanks and trucks placed across the road by the Christians, and waited while negotiations continued. But mostly, there has been a grudging acceptance of their arrival to replace the Israelis. Villagers and militia watched as the trucks full of blue-helmeted troops rumbled by.

As the new forces arrived, Israeli troops who fought their way into Lebanon in a week-long drive against Palestinian forces, maintained a watchful presence. There were signs that some units were being withdrawn. Since Israel's ceasefire announcement on Tuesday, an uneasy peace has settled over the region. Observers have reported sporadic shelling, and some Katyusha rockets fired by pockets of Palestinian resistance. But most front-line Palestinian have also been told to stop firing.

French Paratroopers, on their way to join the Iranians, arrive on Thursday (23 March) at Beirut Airport. The United Nations plan calls for a force of 4,000. This group of nearly 200 crack troops from the 11th Parachute Division are expected to be deployed near the coastal town of Tyre, still held by the Palestinians. Their transport, which will eventually include helicopters and armoured cars, arrived aboard giant Cl60 aircraft.

On Friday (24 March), 400 reinforcements were due. A difficult and lengthy task lies ahead of them, but on Thursday, they had time to sing.

Meanwhile, in Washington, Prime Minister Begin, after concluding talks with President Carter, accused the United States of dropping support for his peace proposals because of objections from Egypt.