Israeli Prime Minister Ehud Olmert on Sunday warned that Israel would hit back hard if guerrillas in Lebanon continue firing on Israel's north.

Olmert said he hoped Israel's initial response, airstrikes against three Palestinian bases near Beirut, would bring an end to the attacks from Lebanon, but the violence was continuing.

"They will receive a clear and harsh response with no hesitation if they do not stop," Olmert warned, calling the attacks "provocative and dangerous." He was speaking to reporters in Jerusalem after meeting Israel's president.

Shortly before Olmert spoke, the army ordered Israelis in two towns near the Lebanon border into bomb shelters during cross-border gunfire and shelling between Israeli forces and guerrillas in Lebanon.

Residents of Kiryat Shemona and Nahariya received instructions to go into shelters, the military said. The military said some rockets exploded in Kiryat Shemona. There were no reports of casualties. Earlier, the military ordered residents of five smaller communities on the border into shelters.

Channel 10 TV reported at nightfall that the fighting had died down and residents were allowed out of the shelters. Briefing reporters at the border, Maj. Gen. Udi Adam, the area commander, said Israel accepted a cease-fire request from the Lebanese government. "I hope that (the fighting) is over," he said.

The clashes after daybreak began when guerrillas fired rockets at northern Israel, and Israeli planes responded with air strikes on Palestinian bases near Beirut.

Later, Hezbollah guerrillas in southern Lebanon opened fire on Israeli soldiers along the border and Israel returned fire, the army said. Hezbollah also launched rockets at northern Israel during the shooting, the army said.

Israel responded with artillery fire and airstrikes into southern Lebanon, the army said.

The military said two soldiers were wounded, one slightly and the other moderately.

Nahariya, a town of 50,000, is located in Israel's on the Mediterranean coast. Kiryat Shemona, in Israel's Galilee panhandle that extends northward into Lebanon, has a population of 21,000.

Channel 2 TV reported this was the third time in the past year that Israelis on the border have been ordered into shelters. The fighting on the border was the most serious since November 2005, when Israeli forces killed four Hezbollah guerrillas who infiltrated into Israel in a disputed border area.

Israeli Cabinet minister Binyamin Ben-Eliezer told Army Radio that Israel has the military power to hit back hard for the attacks, but "the goal now should be to calm the area." Ben-Eliezer, of the moderate Labor Party, is a retired army general and former defense minister.