Hezbollah guerrillas clashed with Israeli soldiers on the southern Lebanese border Wednesday, reviving a two-day old confrontation that saw some of the heaviest fighting in years.

It was unclear what provoked the flare-up. Hezbollah's Al-Manar television said guerrillas engaged an Israeli army unit that had crossed the Lebanese border.

But Israeli security officials said Israeli troops opened fire as they were trying to help an Israeli civilian who had inadvertently flown into Lebanon in a hang glider.

The Israeli troops fired on Hezbollah and opened a gate in the border fence to allow the hang glider pilot to run back into Israel, the security officials said, speaking on condition of anonymity. The officials said Israeli troops did not enter Lebanon.

Lebanese security officials and Hezbollah's Al-Manar television reported the clash as taking place in the Meiss el-Jabal area.

Earlier in the day, Israeli planes dropped thousands of leaflets over Beirut and its suburbs denouncing Hezbollah guerrillas.

Lebanese security officials said the roar of jets was heard over the city before dawn, followed by thousands of leaflets falling from the sky. The officials spoke on condition of anonymity because they are not authorized to speak to reporters.

"To the Lebanese citizens, who protects Lebanon?" read the small leaflet written in Arabic. "Who is lying to you? Who is sending your children to a battle they are not ready for? Who wishes the return of destruction? Who is the tool in the hands of his Syrian and Iranian masters?"

Then in bold letters, it said: "Hezbollah is causing enormous harm to Lebanon," and added that Israel was determined to protect its citizens.

The note was signed "The State of Israel."

Hezbollah dismissed the leaflets as "an expression of Israeli failures in facing Hezbollah," the group's media chief, Mohammed Afif, said in a statement.

The leaflets landed in many parts of the city, including the Palestinian refugee camps in south Beirut. Pamphlets were also dropped over southern Lebanon, the province that borders northern Israel and which is effectively under Hezbollah's control. Lebanon has refused to deploy its army in the province saying it will not defend Israel's border.

In Jerusalem, the Israeli military confirmed that its planes had dropped the leaflets and verified the text.

In June, an Israeli aircraft also dropped pamphlets over Lebanon calling on its government to take control of the border area and put a stop to Hezbollah attacks.

Hezbollah guerrillas attacked Israeli military outposts on Monday and Israel pounded guerrilla positions with artillery and by missiles from warplanes. Four guerrillas were killed and 11 Israeli soldiers were wounded in the clashes in a disputed area near the border in some of the worst fighting in three years.

Hezbollah, the militant Shiite Muslim group, is a close ally of Syria and is backed by Iran. The fighting may have been intended to take the pressure off Syria, which is facing an international probe into the assassination of former Lebanese Premier Rafik Hariri.

Hezbollah has denied it started Monday's fighting. But the U.N. undersecretary-general for political affairs, Ibrahim Gambari, said Tuesday the shooting started on the Lebanese side of the border.

Israel, under military pressure from Hezbollah, withdrew its army from a border buffer zone in southern Lebanon in 2000, ending 18 years of occupation.