The Lebanese Shia Islamist movement, Hezbollah, now has rockets capable of reaching Israel's largest cities, the head of the Israeli military has said.
Major General Gabi Ashkenazi told lawmakers Hezbollah's military wing had tens of thousands of rockets, some with a range of more than 300km (186 miles).
This would potentially put the cities of Tel Aviv and Jerusalem within reach.
Last week, Israel's navy seized a ship it said was carrying hundreds of tonnes of weapons destined for Hezbollah.
"While it is calm at the moment - the borders are quiet in the north and the south - it is a misleading calm," the Israeli newspaper Haaretz quoted Gen Ashkenazi as saying.
"Beyond the fences, the terror groups are gaining strength."
Israel and Hezbollah fought a 34-day war in 2006 during which more than 1,200 Lebanese, mostly civilians, were killed. Some 160 Israelis, most of whom were soldiers, also died.