Israeli warplanes attacked a Syrian army radar position in Lebanon's Bekaa Valley on Sunday, triggering an artillery duel between Hezbollah guerrillas and Israeli troops along the border.

The Israeli airstrike was in retaliation for an attack by Hezbollah two days ago — the second time in less than three months that Israel has lashed back at Syrian positions for action by the guerrillas, who are backed by Syria and Iran.

In the eastern Bekaa Valley, witnesses said at least two Israeli missiles hit a Syrian position in the plain between the two main towns of Zahle and Baalbek.

Two Syrian troops and a Lebanese soldier were wounded, the official Syrian news agency SANA reported. Lebanese security officials said at least two Syrian soldiers were hit, but did not mention any Lebanese casualties.

The Bekaa Valley is dotted with Syrian radar, anti-aircraft and tank positions, part of a force of some 25,000 deployed in Lebanon, especially in the Bekaa near Syria's border, since 1976. The Syrian government made no immediate comment on the Israeli strike.

The instant Hezbollah response to the Israeli strike was reminiscent of the worst days of the 20-year border war that finally saw Israel end its occupation of southern Lebanon a year ago.

Hezbollah fired rockets and mortars at two Israeli military positions, witnesses said. Israel responded with its own fire, and Lebanese security officials said one Lebanese farmer, 60-year-old Kassem Atwi, was injured in the Israeli shelling.

In Israel, a government statement said the initial airstrike was in retaliation for Hezbollah attacks. "This criminal activity by Hezbollah takes place under the authorization of Syria," Israel's Cabinet said in a statement.

On Friday, Hezbollah guerrillas fired anti-tank missiles at Israeli army positions in the disputed Chebaa Farms area along the Israeli-Lebanese border, wounding one soldier. Israeli warplanes responded by firing on suspected guerrilla infiltration routes.

Hezbollah has vowed to continue fighting Israel until it vacates the Chebaa Farms area. The territory is part of the Golan Heights, which Israeli occupied from Syria. However, Syria and Lebanon claim the land belongs to Lebanon.

Israeli warplanes destroyed a Syrian radar station on April 16, killing three Syrian soldiers, in retaliation for an earlier Hezbollah attack. After that strike, neither Hezbollah nor Syria immediately retaliated.

The leader of the Islamic militant guerrilla group, Sheik Hassan Nasrallah, warned Sunday of a tougher Hezbollah response.

"I don't want to make threats, but for sure we will deal with it differently," he said at a Hezbollah rally not far from the radar station targeted Sunday. Israel was "playing with fire" and the airstrike against the Syrians "won't do them any good," he said.

Before the strikes, Lebanon and Syria issued a joint statement warning Israel against attacking Lebanon.

"Israel will be held responsible for the consequences of any further retaliation on the entire region, world security and peace," Syrian Foreign Minister Farouk al-Sharaa and his Lebanese counterpart, Mahmoud Hammoud, said in the statement Saturday.