"It has been done. The resistance now owns precision missiles" as part of its weaponry, Hezbollah chief Hassan Nasrallah said in a televised address during the key Shiite commemoration of Ashura.

Israel this month acknowledged carrying out more than 200 strikes over the past 18 months in war-torn Syria, where Hezbollah fights alongside Israel's arch-foe and Shiite powerhouse Iran in support of the Damascus regime.

Israel has said it is working to stop Iran from entrenching itself military there and to keep Hezbollah from acquiring sophisticated arms.

"Attempts in Syria to block the way towards this (missile) capability" have failed, Nasrallah said.

"If Israel imposes a war on Lebanon, it will face a fate that it never would have expected."

Israel has fought several conflicts against Hezbollah, the last in 2006.

The Israeli military believes Hezbollah has between 100,000 and 120,000 short-range missiles and rockets, as well as several hundred longer-range missiles.

Israeli Prime Minister Benjamin Netanyahu said Nasrallah should not think twice but "at least 20 times" before deciding whether to attack Israel.

"If he seeks conflict with us, he will receive a blow he cannot even imagine," Netanyahu said in a statement.

- Iran's 'dangerous deadline' -

Late Monday, an Israeli raid hit Syria's coastal province of Latakia to prevent what it said were deliveries of materials for advanced weaponry to Hezbollah.

The same evening Syrian air defences downed a Russian military plane by mistake, killing all 15 on board.

Russia backs Syria's government militarily and it was the worst case of friendly fire between the two allies since Moscow intervened in the conflict in 2015.

On Tuesday, Netanyahu said his country was "determined to stop Iranian military entrenchment in Syria, and the attempts by Iran, which calls for the destruction of Israel, to transfer to Hezbollah lethal weaponry (to be used) against Israel".

Nasrallah accused the Israelis of trying to kill him "day and night". He has lived in a secret location for decades and rarely appears in public.

The Hezbollah chief also reiterated his support for Iran, after the United States withdrew from a landmark nuclear deal in May.

Washington reimposed sanctions on the Islamic republic last month, and a new round of even harsher sanctions targeting Iran's vital oil sector is set to go into effect in early November.

"It is our duty today to stand by Iran, who in a few weeks' time will face a dangerous deadline -- the start of American sanctions," he said.

Nasrallah accused the United States of "going to all the world's capitals in a bid to besiege" Iran, as Washington seeks support for its measures against the country.