Qassem spoke in a televised address after meeting Iran's top security chief Ali Larijani, whose country has long backed the Lebanese militant group.

Hezbollah emerged badly weakened from last year's war with Israel, and under US pressure the Lebanese government has ordered the army to devise a plan to disarm the group by the end of the year.

Iran, whose so-called "axis of resistance" includes Hezbollah, has also suffered a series of setbacks, most recently in the war with Israel that saw the United States strike its nuclear sites.

"The government is implementing an American-Israeli order to end the resistance, even if it leads to civil war and internal strife," Qassem said.

"The resistance will not surrender its weapons while aggression continues, occupation persists, and we will fight it... if necessary to confront this American-Israeli project no matter the cost," he said.

Qassem urged the government "not to hand over the country to an insatiable Israeli aggressor or an American tyrant with limitless greed".