Two U.S. Army soldiers who made a wrong turn into a Shiite Moslem neighborhood were abducted and held for two hours today by Shiite militiamen until their release was negotiated by the Lebanese Army.

A U.S. Marine spokesman said an officer and an enlisted man assigned to classified technical duties in the Marine peace-keeping contingent were disarmed, searched and interrogated before they were released and returned to their unit near Beirut International Airport. They were the first U.S. troops abducted by any of the factional militias here.

Marine spokesman Maj. Robert Jordan said the soldiers were released after a Lebanese Army officer, Col. Hasham Gabber, telephoned the head of the Shiite group Amal, Nabih Berri, who ordered the militia to deliver the prisoners to his home. Their sidearms were returned when they were released.

Jordan said that on the basis of the Shiite militia's mistaken claim that they had captured two marines, a headcount of the Marine contingent was made but turned up no missing troops. The identity of the Army technicians, whose names were not released, was not known until they were returned, Jordan said.

He said the two made a wrong turn in a jeep on their first trip to downtown Beirut and did not know they were in a militia-controlled zone. "They are a little embarrassed," Jordan said.

The incident occurred on a day marked by fewer cease-fire violations than in the previous three days, although a Lebanese Army unit near Suq al Gharb in the hills east of Beirut came under sniper fire.

The Beirut airport, which has been closed since Aug. 28, reopened following a meeting of a military committee representing the Lebanese Army and the three major militias of the Shiites, Christians and Druze. Druze in the strategic hills overlooking the capital had threatened to shell any civilian or military aircraft that attempted to land.

In what many Lebanese regard as a symbol of normalcy, a Boeing 707 of Middle East Airlines landed with passengers returning from a pilgrimage to Mecca in Saudi Arabia.