Hezbollah leader Sayyed Hassan Nasrallah has said that thousands of rockets will rain down on Israel if it attacks Lebanon.
"Israel, which was shaken by a handful of Fajr-5 rockets during eight days - how would it cope with thousands of rockets which would fall on Tel Aviv and other (cities) ... if it attacked Lebanon?"
Nasrallah told thousands of supporters who massed in the southern suburbs of Beirut to commemorate Ashura on Sunday.
He was referring to eight days of violence between Israel and Hamas, which rules the Palestinian Gaza Strip that ended in an Egyptian-brokered ceasefire earlier this week.
The Fajr-5s, with a range of 75 km (45 miles) - able to strike Tel Aviv or Jerusalem - and 175 kg (386 lb) warheads, are the most powerful and long-range rockets to have been fired from Gaza.
"If the confrontation with the Gaza Strip ... had a range of 40 to 70 km, the battle with us will range over the whole of occupied Palestine - from the Lebanese border to the Jordanian border, to the Red Sea," Nasrallah said.
Hezbollah could hit targets "from Kiryat Shmona - and let the Israelis listen carefully - from Kiryat Shmona to Eilat", he said, referring to Israeli's northernmost town on the Lebanese border to the Red Sea port 290 miles further south.
"The time when Israel could terrorise us has expired," he said.
Hezbollah, which fought Israel to a standstill in a 34-day war six years ago, says it has been re-arming since then and has a far deadlier arsenal than Hamas.
Nasrallah has said Hezbollah could kill tens of thousands of people and strike anywhere inside Israel if hostilities break out again.
According to Pentagon officials, Hezbollah has 50,000 missiles, including some capable of reaching Tel Aviv.