Prime Minister Benjamin Netanyahu said on Sunday that Israel would act against Iran, not just its allies in the Middle East, if needed, reiterating that Tehran was the world's greatest threat.
Holding a piece of what he said was an Iranian drone after its incursion into Israeli airspace earlier this month, Netanyahu told the Munich Security Conference: "Israel will not allow the regime to put a noose of terror around our neck.
"We will act if necessary not just against Iran's proxies but against Iran itself," he said.
Addressing the Munich event for the first time, Netanyahu urged gathered US and European officials and diplomats to counter Iran immediately, displaying a map showing what he said was Iran's growing presence in the Middle East.
He said Iran was increasing its power as the US-led coalition against Islamic State in Iraq and Syria regains territory from militants.
"The unfortunate thing is that as ISIS compresses and Iran moves in, it is trying to establish this continuous empire surrounding the Middle East from the south in Yemen but also trying to create a land bridge from Iran to Iraq, Syria, Lebanon and Gaza," Netanyahu said.
"This is a very dangerous development for our region."
Tensions surged on February 10 when anti-aircraft fire downed an Israeli warplane returning from a bombing raid on Iran-backed positions in Syria.
That was the most serious confrontation yet between Israel and Iranian-backed forces based across the border.