Israeli forces have struck at suspected guerrilla positions in southern Lebanon, after an exchange of rocket and artillery fire with Hezbollah fighters. The attack came after two hours of heavy artillery exchanges between the two sides that erupted at daybreak in the disputed Shebaa Farms border region.

An Israeli military spokesman said Israel used helicopters and artillery in strikes in the Shebaa Farms area after Hezbollah guerrillas attacked Israeli positions. Hezbollah issued a statement in Beirut saying Israeli troops had been ambushed after infiltrating Hezbollah-controlled areas inside Lebanon and that a number of Israelis had been killed.

Wednesday, Israeli planes bombed targets on the Lebanese side of the border. The Israeli army said the action was in response to a Hezbollah attack on Israeli outposts.

Two members of the Israeli parliament have called for a tough response to the fighting. Yuval Steinetz, who chairs the Foreign Affairs and Defense committee, said the Lebanese government should be held accountable for failing to exercise control over its territory. Efraim Sneh, of the opposition Labor Party, said it is Syria and not Lebanon that gives Hezbollah permission for attacks on Israel.

Cross-border clashes have been regular occurrences over the course of the past four years, ever since Israeli forces pulled out of territory in southern Lebanon they had occupied for 18 years.

The Shebaa Farms area is a stretch of land near Lebanon's southeastern border. Israel captured the territory when it seized the Golan Heights from Syria in the 1967 war. Lebanon claims Shebaa Farms but the United Nations says it belongs to Syria, and that Syria and Israel should negotiate the question of ownership.