Israel unleashed more airstrikes on Lebanon on Wednesday and Hezbollah militants targeted Israel's Mossad spy agency headquarters and fired salvoes of rockets into northern Israel in the heaviest exchanges between the arch-foes in a year.
The Israeli military said a single surface-to-surface missile was intercepted by air defense systems after it was detected crossing from Lebanon.
Israeli military spokesman Nadav Shoshani said he could not confirm what Hezbollah's target was when it fired the missile from a village in Lebanon.
"The result was a heavy missile, going towards Tel Aviv, towards civilian areas in Tel Aviv. The Mossad headquarters is not in that area," he said.
Warning sirens sounded in Tel Aviv, Israel's economic capital, but there were no reports of damage or casualties. Sirens also sounded in other areas of central Israel, including the city of Netanya.
The Iran-backed Hezbollah said in a statement it had fired a missile on Wednesday morning targeting the Mossad headquarters in a Tel Aviv suburb "in support of our steadfast Palestinian people in the Gaza Strip ... and in defense of Lebanon and its people."
It blamed Mossad for the recent assassination of its leaders.
It has also accused the spy agency of carrying out an extraordinary operation last week in which the communications devices of its members were booby-trapped and exploded, killing 39 people and wounding nearly 3,000 in the worst security breach in its history. Israel has neither confirmed nor denied involvement.
The Israeli military has been mounting its heaviest airstrikes in a year of conflict this week, targeting Hezbollah leaders and hitting hundreds of sites deep inside Lebanon while Hezbollah has fired barrages of rockets into Israel.
There was no let up on Wednesday. Israel said its warplanes were currently carrying out extensive strikes in south Lebanon and the Bekaa Valley.
Three people were killed and nine others injured in an Israeli strike on the Lebanese Shi'ite town of Maaysrah in the Christian-majority Keserwan region on Wednesday, Lebanon's health ministry said. It was the first time the area has been struck in the recent hostilities.
Israel has expanded the zones it has been striking since Tuesday night, with attacks for the first time on the beach resort town of Jiyyeh just south of Beirut and Maaysrah.
Israeli authorities said the Galilee region of northern Israel was hit by heavy Hezbollah barrages on Wednesday morning.
In one salvo about 40 rockets were fired. Some were intercepted in mid-air, others struck open areas or penetrated air defenses into populated areas, they said.
In the Israeli town of Safed, an assisted living facility was hit but no injuries were reported, the authorities said.
Near-daily exchanges of fire in the Israel-Lebanon border area started after war broke out last October between Israel and the Palestinian militant group Hamas in the Gaza Strip on Israel's southern border, with Hezbollah saying it was acting in solidarity with its ally Hamas.
Israel's focus has now turned to its northern frontier and southern Lebanon.
Since Monday morning, the Israeli offensive has killed 569 people, including 50 children, and wounded 1,835 in Lebanon, Health Minister Firass Abiad told Al Jazeera Mubasher TV.
Half a million people are estimated to have been displaced in Lebanon, Foreign Minister Abdallah Bou Habib said. In Beirut, thousands of people who fled from southern Lebanon were sheltering in schools and other buildings.
Range of Options
Also on Wednesday, the Israeli military said a drone crossing into Israeli territory from Syria was intercepted by fighter jets south of the Sea of Galilee.
The Islamic Resistance armed groups in Iraq said in a statement they had attacked a target in the occupied Golan Heights via a drone.
Israel military leaders have said they are prepared for a range of options as it battles Hezbollah, a more sophisticated, disciplined and experienced enemy than Hamas which was created by Iran's elite Revolutionary Guards to counter an Israeli invasion of Lebanon in 1982.
But Hezbollah has proven resilient over its decades-long hostilities with Israel, recovering from heavy blows and defying superior firepower. Iran's Supreme Leader Ayatollah Ali Khamenei said on Wednesday that killing important Hezbollah figures would not bring it to its knees.
Israeli troops have been training for months for a possible ground operation inside Lebanon aimed at securing its northern border and enabling thousands of Israeli residents who fled for their safety to return to their communities, one of Prime Minister Benjamin Netanyahu's government's top war priorities.
Israel's close ally the United States is sticking by it despite its concerns about mass civilian casualties. While Arab states have condemned Israel's military campaigns, they have not taken strong steps to force it to rein in the most powerful military in the Middle East.
On Tuesday, a strike in Beirut killed senior Hezbollah commander Ibrahim Qubaisi, who headed the group's missile and rocket force.
'Lebanon Is at the Brink'
The U.N. Security Council said it would meet Wednesday to discuss the conflict which was intensifying across the region.
"Lebanon is at the brink. The people of Lebanon – the people of Israel – and the people of the world - cannot afford Lebanon to become another Gaza," U.N. Secretary General Antonio Guterres said.
Israeli Defence Minister Yoav Gallant said the attacks had weakened Hezbollah and would continue.
Hezbollah "has suffered a sequence of blows to its command and control, its fighters, and the means to fight. These are all severe blows," he told Israeli troops.