Western media reports said yesterday Israel has carried out extensive air strikes on southern Lebanon, saying its warplanes have hit more than 100 Hezbollah rocket launchers and other "terrorist sites" including a weapons storage facility.

According to the BBC, the Israel Defense Forces (IDF) said the launchers were ready to be fired against Israel. It was not immediately clear if there were any casualties.

Lebanon's state-run National News Agency said Israel carried out at least 52 strikes in the south of the country on Thursday evening, and that Lebanon had also launched strikes on military sites in northern Israel.

Earlier, Hezbollah leader Hassan Nasrallah reportedly said deadly explosions earlier in the week "crossed all red lines", accusing Israel of what he said represented a declaration of war.

Israel has not said it was behind the attacks - which saw pagers and walkie-talkies explode simultaneously across the country - on Tuesday and Wednesday, and which Lebanese authorities said killed 37 people and wounded 3,000.

But Israeli Defense Minister Yoav Gallant has been cited as saying that Israel is embarking on a "new phase of the war", concentrating more of its efforts on the north.

Quoting Israeli official, NBC News says the attack on southern Lebanon on Thursday involved airstrikes and artillery.

The attack on southern Lebanon involved airstrikes and artillery, but Israeli ground forces had not crossed the border, an Israeli official told NBC News.