Israeli aircraft have attacked suspected bases of the militant Islamic group Hezbollah in southern Lebanon, in retaliation for the killing of an Israeli youth on Sunday.

Israeli air force helicopters struck at a position in southern Lebanon from which the Hezbollah had fired anti-aircraft shells into Israel just hours earlier. There was no immediate word of casualties or damage from the Israeli action.

The Israel raid followed the Hezbollah shelling that Israeli authorities said killed a 16-year-old Israeli boy in the town of Shlomi, in northern Israel, on Sunday and wounded four others.

Hezbollah denied it was deliberately targeting the area, and insisted it had fired only at Israeli jets that had flown over Lebanon.

Israel's deputy defense minister, Ze'ev Boim, rejected the statement. He said that Hezbollah had not targeted Israeli aircraft, but Israeli civilians.

Israel's foreign minister, Silvan Shalom, warned that Israel would be forced to defend itself, if Syria, the main power broker in Lebanon, and the Lebanese government failed to prevent the Hezbollah from carrying out further attacks.

Gideon Meir, a spokesman for the Israeli Foreign Ministry, says the ongoing Hezbollah missile attacks are proof that the Hezbollah wants to use terror to undermine peace efforts and destabilize the region.

He said Israel would not stand by and allow itself to be the target of Hezbollah's operations. "Israel has a right of self-defense and has responsibility to defend its citizens, and so it will do," he said.

Israel has also lodged a protest in the United Nations, saying it is absurd that Syria, a country that supports the Hezbollah, should be currently serving as head of the U.N. Security Council.

Israel's ambassador to the United Nations, Dan Gillerman, warned the world body that the actions of the Hezbollah guerilla fighters in southern Lebanon are raising tensions in the Middle East and undermining efforts to reach a comprehensive peace in the region.