The Israeli Army mounted one of its largest security operations in southern Lebanon in recent months today, detaining more than 50 people during a sweep of several Moslem Shiite villages in the mountains east of Tyre.

Israeli military officials said here tonight that one Lebanese man, whom they described as a "known terrorist," was shot and killed while trying to escape and that at least two, and possibly as many as six, Lebanese were slightly wounded as a result of the operation. They said the operation, which reportedly included the use of tanks and armored personnel carriers, was carried out as part of an Israeli policy "to prevent and frustrate attacks on our forces in Lebanon."

However, Timur Goksel, the spokesman at the United Nations southern Lebanon headquarters at Naqura, said U.N. forces discovered three dead and five wounded after the Israeli Army sweep through the area, which began at about 5 a.m. today. The dead and wounded were found in the villages of Tura and Marakah, two of the seven villages that Israeli soldiers surrounded and searched, Goksel said.

The U.N. spokesman said there were also unconfirmed local reports that seven other Lebanese were wounded as a result of the operation.

Goksel said two of the dead were a woman and a 14-year-old girl. Meanwhile, Israel radio reported that during the searches of the villages, Israeli soldiers were surrounded by crowds, made up mostly of women, who attacked them with metal pipes and knives. The radio said the soldiers fired their weapons in the air to escape the crowds.

Goksel said the circumstances surrounded the deaths of the girl and the woman had not been determined, while Israeli military officials flatly denied that their deaths and the additional number of people reported wounded were caused by today's sweep. They refused to characterize the size of the operation, but Goksel said it was one of the largest conducted recently in the area.

Many of the mountain villages east of Tyre that were surrounded and searched today have been growing centers of Moslem Shiite fundamentalism and of resistance to the Israeli occupation of southern Lebanon. Some Israeli officials have warned publicly that the rise of Moslem fundamentalism in the area could eventually confront Israel with a "religious war" in the territory it now occupies.

The tension between the villagers and the Israelis has been building steadily. Two months ago in Marakah, one of the villages that was searched today, a militia leader told reporters, "We are expecting a great attack by the Israelis."

The Israeli military officials said that about 30 people were arrested during the operation, including a "known squad" that was captured with its weapons. They said about two dozen others also were detained for questioning but that most of them were expected to be released later.

The officials said that the roughly 30 people who were arrested on the basis of "hard evidence" have been involved in "planning and perpetrating attacks" on Israeli forces. They said "large quantities of weapons were found" during the searches and that these weapons "were prepared for attacks on Israeli forces."

The Israeli Army action came on the same day that the 10th session in the Israeli-Lebanese military talks was scheduled to take place at the U.N. headquarters in Naqura. Goksel said that the meeting was canceled because of bad weather and high winds that prevented U.N. helicopters from bringing the Lebanese military delegation to southern Lebanon from Beirut.

He said the next meeting was scheduled for Monday.

Today's Israeli military action, however, could have an impact on the negotiations, which are aimed at arriving at security arrangements in southern Lebanon that Israel has set as a condition for a withdrawing its troops from the territory.

The negotiations began on Nov. 8 and almost immediately were broken off by the Lebanese to protest the arrest by Israel of four members of the Lebanese Moslem Shiite militia Amal on the same day that the talks began. As part of an agreement brokered by U.N. officials, the talks were resumed, and the four Amal members were released after they were interrogated by the Israelis.

The Israelis insist that security operations such as today's sweep through the mountain villages are unrelated to the negotiations and not meant to pressure the Lebanese or disrupt the talks. They said today that the arrests were made as part of a policy "that has been reiterated at the Naqura talks, in which the security of our forces in southern Lebanon takes precedence over any other consideration."

The negotiations have made little apparent progress toward achieving security arrangements and an Israeli troop withdrawal. According to Israeli officials, the talks are now deadlocked on the future role of the U.N. force in southern Lebanon.

Israel wants the U.N. force redeployed to the north, where it would serve as a buffer for an Israeli-backed militia in southern Lebanon, while the Lebanese insist that the U.N. soldiers be confined along the Israeli-Lebanese border.

U.S. Assistant Secretary of State Richard W. Murphy returned to the Middle East last week in a renewed attempt to break the deadlock. Murphy met today in Tel Aviv with Israeli Defense Minister Yitzhak Rabin and other senior officials.

Amal leader and South Lebanon Minister Nabih Berri described the Israeli action in the south today as a "massacre," special correspondent Nora Boustany reported from Beirut. He proclaimed a general strike throughout the south for Saturday and called on international institutions to move immediately to put a stop to Israel's actions.