Ten Lebanese Army armored personnel carriers were among the weapons captured by Druze militiamen in fighting last week, an Army spokesman said today.

The spokesman also confirmed that more than 50 Lebanese soldiers were captured in the battles in the mountains south of here and that "three or four" Army positions were overrun during the fighting. It was the first heavy fighting for the Army since the 1975-1976 Lebanese civil war, in which it virtually disintegrated.

The losses were clearly an embarrassment and raised the question of how effectively the government of President Amin Gemayel has strengthened the Army. A principal goal of U.S. policy in Lebanon has been creation of an Army capable of ensuring security in the face of attacks by private militias after foreign forces pull out.

Col. Simon Cassis, chief of Lebanese intelligence, entreated western journalists today not to "judge the effectiveness of the Army" on the basis of its performance last week.

The Army has said the losses came because the positions were only lightly armed and could not be resupplied in time, partly because of the heavy fighting and partly because Israeli soldiers blocked resupply vehicles. Israel has denied intentionally preventing resupply of Lebanese forces.

Lebanese Army spokesmen also said numerous supplies of small arms and ammunition were taken from the Army during the fighting. Last week, Jordan gave 20 M48 tanks and 15 armored vehicles to the Lebanese Army. The United States has sold it more than 200 armored personnel carriers, 93 vehicles to carry mortars and 25 mobile command posts.

The Army is preparing to expand its control beyond the capital and its suburbs when occupying Israeli forces pull back from military positions in the mountainous area south of Beirut. Rebellious Moslem Druze militiamen who have engaged in numerous battles with Christian fighters in the region have insisted on a new political arrangement before Army deployment in the mountains. The Druze fear that the Army might ally itself with their Christian foes.

Christian and Druze militia have battled in the mountains for nearly a year. Cassis said he believed the occupying Israeli forces were "helping both sides."

An Army spokesman said Druze militiamen still held positions they had taken during heavy ground fighting Wednesday and Thursday around the village of Kfar Matta, 10 miles south of Beirut. He said the Army was still in control of its battalion headquarters there. Between the forces was an Israeli tank battalion, he said.

Beirut's international airport remained closed for the fifth day today because of the threat of renewed shelling by the Druze.

[U.S. envoy Robert C. McFarlane met with Foreign Minister Elie Salem and informed sources said the discussions focused on the battles with Druze fighters, The Associated Press reported.]