Qassem gave a televised address after meeting with Iran's 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 the Lebanese government -- under US pressure -- has ordered the army to draw up 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 its own war with Israel, which also saw the United States strike its nuclear facilities.

"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 urged the government "not to hand over the country to an insatiable Israeli aggressor or an American tyrant with limitless greed", adding the state would "bear responsibility for any internal explosion and any destruction of Lebanon".

Prime Minister Salam later denounced the remarks, saying on X that they "constitute an implicit threat of civil war".

He added that "any threat or intimidation related to such a war is totally unacceptable".

Salam also hit back at Hezbollah's characterisation of the disarmament push as an American-Israeli effort.

"Our decisions are purely Lebanese, made by our cabinet, and no one tells us what to do," he said.

"The Lebanese have the right to stability and security... without which the country will not be able to recover, and no reconstruction or investment will take place."

Before the war with Israel, Hezbollah was believed to be better armed than the Lebanese military.

It long maintained it had to keep its arsenal in order to defend Lebanon from attack, but critics accused it of using its weapons for political leverage.

Qassem said Friday that Hezbollah and its political ally Amal would not be organising any street protests against disarmament at this time, but threatened to do so in future.

Iran's Supreme National Security Council chief Larijani was in Beirut this week, and held talks with Qassem as well as with President Joseph Aoun.

Iran has expressed its opposition to the government's disarmament plan, and has vowed to continue to provide support, with Lebanese officials recently hardening their tone towards Hezbollah and its patron.

Both the president and the prime minister took issue with Iran's recent statements during Larijani's trip, with Salam saying Lebanon rejects "any interference in its internal affairs".