Hezbollah's military arm, the Islamic Resistance, said in a statement that its guerrillas had "destroyed a Zionist warship ... off Tyre."

But an Israeli army spokesman denied that any of its ships off Lebanon's coast had been targeted by a missile, saying: "The report is simply not true."

Hezbollah had vowed revenge following the killing of 52 people, most of them women and children, in an Israeli air raid on the village of Qana on Sunday.

On July 14, just two days after Israel launched its offensive against Lebanon, Hezbollah fired a rocket into warship off Beirut, killing four Israeli sailors.