Israeli Army helicopters showered parts of southern Lebanon today with leaflets announcing imposition of a nighttime curfew and severe travel restrictions and warning that anyone violating the new regulations "will endanger his life."

The extraordinary measures, aimed at reducing the mobility of Lebanese Shiite Moslem guerrillas who have been attacking Israeli soldiers, included a total ban on motorcycle traffic in the Israeli-occupied territory and a requirement that all vehicles traveling on the roads include at least two people.

The Arabic-language leaflets dropped by the helicopters this morning said that unattended vehicles found by the side of roads will be blown up. They said the curfew, forbidding residents to leave their homes, was to be in effect from sundown until sunrise and added that "it is absolutely forbidden to be outside the villages during the curfew period."

Inexplicably, the leaflets were dated Feb. 18 and said the regulations went into effect on that day.

Israeli radio described the reaction of Lebanese to the regulations as "complete astonishment" and said Israeli officers in the area also appeared to have been caught off guard and could not answer the questions of local residents. But the radio quoted an unnamed Israeli officer as saying, "When the subject is the safety of our soldiers, we don't care if someone is surprised or if someone complains that his freedom has been curtailed."

Sources in southern Lebanon said the leaflets were dropped in Tyre and the Shiite villages around Tyre that have been the scene of most of the recent attacks on Israeli forces. The regulations were addressed to Lebanese who live south of the Litani River, a predominantly Shiite area.

The move is part of an Israeli crackdown in the Tyre area that in the last week has included searches of several villages, the arrests of hundreds of men and the destruction of more than a dozen houses. Today, Israeli Army units sealed off and searched the village of Sharifa, about 10 miles east of Tyre, and arrested six people, according to sources in the area.

The Israeli Army also issued regulations barring foreign journalists based in Beirut from entering the Israeli-occupied area of Lebanon, The Associated Press reported. The Army said journalists would be allowed into the occupied area only from Israel and only if accompanied by an Israeli press officer and security escort. Stories filed by the journalists would be subject to Israeli censorship.

Israel Radio quoted Defense Minister Yitzhak Rabin as telling a parliamentary committee here today that during the crackdown the Israelis had killed 15 people, wounded 28 and deported 19 to Syrian-controlled territory in Lebanon. He said those killed and wounded were "terrorists."

The curfew and travel restrictions, which indicated Israel's increasing determination to minimize its casualties while planning to withdraw from southern Lebanon, were criticized by advocates of an accelerated withdrawal.

In a radio interview, Shulamit Aloni, leader of the left-wing Citizens' Rights Movement in Israel's parliament, said:

"From the legal and humanitarian point of view, this is a scandal. If we are in fact a democratic society, collective punishment of this type might be proper in the midst of a war against an enemy, but when you are in a situation with a civilian population that we supposedly came to save, it just doesn't make sense."

Aloni said the only solution was for Israel to "instruct the Army to get out of there as soon as possible."

A military official said tonight that the ban on motorcycles, a popular form of transportion in rural southern Lebanon, came about because of hit-and-run attacks on Israeli forces by guerrillas who escaped on motorcycles. He said the requirement that all vehicles include at least one person in addition to the driver was meant to discourage the use of suicide car bombs.

In the first three days after the evacuation of the Sidon area, the Israelis suffered three killed and five wounded as a result of attacks in the area still under its control. This led to the crackdown in the Shiite villages east of Tyre.