Hezbollah leader Sheik Hassan Nasrallah defiantly told Israel yesterday that his guerrillas were "in their full strength and power" and vowed to beat any Israeli ground invasion.

In a speech broadcast on his Al-Manar TV, Nasrallah denied Israeli statements that Iranian troops were helping his guerrillas in the war with Israel. He urged Arabs and Muslims worldwide to support his guerrillas, saying his group was fighting Israel on behalf of them.

"Today, especially in this sensitive moment and after several military achievements and surprises, Hezbollah is not fighting a battle for Hezbollah or even for Lebanon. We are now fighting a battle for the (Islamic) nation. Where does the nation stand on this battle?" he said.

"The peoples of the Arab and Islamic world have a historic opportunity to score a defeat against the Zionist enemy . . . we are providing the example," he added.

Nasrallah looked tired and his speech was slower than usual. The video's sound quality was poor, suggesting it was made in a makeshift studio.

The guerrilla leader said he was speaking at 11am our time yesterday, dispelling reports that he had been hurt in the massive Israeli bombing of his headquarters overnight as some Israeli reports said. The message was broadcast about six hours after that time.

Nasrallah's office, residence and the headquarters of his leadership were destroyed in Haret Hreik, a south Beirut suburb and a Hezbollah stronghold. The area was hit with repeated missile strikes from Israeli warplanes.

The TV station itself was knocked off the air for a few minutes yesterday and officials said its main building was badly damaged by Israeli missiles. It continued to broadcast last night.

Nasrallah sought to boost the morale of his supporters. "We are still in our full strength and power. We choose the time and place [for the battle]. We still manage our affairs in an accurate manner," he said.