Hezbollah fighters have fired a barrage of rockets into northern Israel as the group fought up to 6,000 Israeli troops across five fronts in southern of Lebanon.

Some 190 Hezbollah rockets - the most fired in a single day so far in the conflict - were fired across the border from Lebanon hitting further south than ever before, police and Israeli radio reports said.

Rockets landed near the Israeli town of Beit Shean, about 70km from the border and in the West Bank near the town of Jenin.

One US-born Israeli was killed as he fled for a bomb shelter in Kibbutz Saar, a communal farm near the northern border town of Nahariya. 19 Israeli civilians have died during rocket attacks in the last three weeks.

At least 21 people were wounded during Wednesday's rocket attacks, a police spokesman said.

The rocket barrage came after a two-day lull and claims by Israeli officials that they had considerably weakened Hezbollah’s military capability.

The northern Israeli village of Beit Hillel was hit just before Israel's army chief, Lieutenant General Dan Halutz, spoke to reporters there.

Hezbollah 'damaged'

Halutz said Israel has dealt the Hezbollah a damaging blow, including killing hundreds of fighters and damaging their supplies of medium and long-range rockets. He said the army would also consider renewing its airstrikes deep into Lebanon.

"We will need to evaluate the airstrikes in the depth of Lebanon, especially in Beirut," Halutz said. "I assume the matter will come up for authorisation in the next day or two."

Five Israeli soldiers were wounded as they clashed with Hezbollah fighters on five fronts in south Lebanon on Wednesday, the army said. Israeli warplanes and artillery struck as tanks led soldiers into border villages.

Three of the soldiers were injured in fighting near the village of Mhaibib, in the southeast corner of Lebanon, an army spokesman said.

The other two were injured near the border village of Aita al-Shaab, further to the west, where three Israeli soldiers were killed and 25 injured in clashes with Hezbollah on Tuesday.

Thirty-six Israeli soldiers have been killed since the start of the offensive on July 12.

Baalbek raid

The upsurge in rocket attacks followed a raid by on a Hezbollah-run hospital near Baalbek by Israeli troops in helicopters. The army said five suspected Hezbollah fighters were seized. Hezbollah said only civilians were taken.

Aljazeera's correspondent in Beirut said the raid was targeting Hezbollah's leader Hassan Nasrallah.

At least 13 civilians were killed when Israeli warplanes hit Jammaliyeh, a village near Baalbek, and six died in air strikes elsewhere in the Bekaa Valley, security sources said.

A Lebanese army soldier was also killed and two were wounded in an Israeli airstrike on their post in the south, the army said.

At least 643 people in Lebanon and 55 Israelis have been killed in the conflict which has now entered its fourth week.

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Some 190 Hezbollah rockets hit northern Israel on Wednesday. (Al-Jazeera)