srael faces a growing potential of a devastating war in Gaza like the 2006 conflict in southern Lebanon that killed hundreds and wrecked large parts of the region, a senior Israeli official said today.

Sallai Meridor, Israel's ambassador to the United States, said the extremist group Hamas is importing longer-range missiles, anti-tank weapons, mines and other weapons into Gaza through the border with Egypt.

Coming with the weapons are Iranian-trained insurgents and weapons experts "who are self-identified with al-Qaida," he said, citing a report by the chief of Israeli intelligence.

Hamas has fired hundreds of rockets into Israel in recent weeks, including five yesterday that struck the town of Sderot in southern Israel.

Related Israeli air strikes yesterday killed three Hamas members and wounded four others, according to Israeli government accounts.

In the fighting in southern Lebanon in July and August 2006, Hezbollah insurgents fired massed salvos of rockets into Israel. Dug-in Hezbollah fighters were able to resist Israeli air strikes, so that when Israeli tanks and infantry moved in, they met with fierce resistance. In one incident closely studied at the Pentagon, Hezbollah infantry using anti-tank weapons destroyed an Israeli tank platoon.

But the heavy Israeli air strikes, against Hezbollah positions that seemed deliberately planted in heavily populated civilian areas, created acres of rubble and civilian casualties, igniting an international uproar and demands for an immediate cease-fire.

A war in Gaza could be even more devastating.

Meridor, speaking today at a breakfast with defense reporters, described the growing threat in Gaza as similar to that in southern Lebanon in 2006, with fighters building deep-buried fighting positions protected with mines and anti-tank weapons.

The difference is, he said, "is that Gaza is extremely populated. In Lebanon there was a lot of shooting from villages. Gaza is one large village. Tactically, that makes a difference."

Meridor said the "most reasonable" way to deal with the problem is for Egypt to seal the border with Gaza, which has been administered by Hamas since it seized power there last June.

Asked whether Washington has given a "green light" for an Israeli military incursion into Gaza, Meridor said, "It's not a question of a green light, but of Israel's right and need to defend itself."