"The ceasefire must be comprehensive, without a separation between the south and the rest of Lebanon, and without the Israeli enemy having the freedom to kill," Qassem said in a written message broadcast on his group's Al-Manar television channel.

Envoys from Israel and Lebanon had held a fourth round of US-brokered talks in Washington on Wednesday, agreeing to implement a ceasefire that hinged on Hezbollah halting its attacks.

But a Hezbollah official told AFP on Thursday that the group rejected the agreement, which Lebanese President Joseph Aoun had earlier called the "last chance" to reach a comprehensive truce.

The official said on condition of anonymity that the position was passed on to parliament speaker Nabih Berri, a Hezbollah ally who has been acting as an intermediary and who "shares this position".

Qassem urged the government to halt "the farce and humiliation called direct talks" with Israel and vowed that "as long as our villages are unsafe -- being bombed, destroyed and our people killed -- the settlements (north Israel) are unsafe".

According to a joint statement after the US-led talks in Washington on Wednesday, the proposed "ceasefire is contingent on a complete cessation of Hezbollah fire and the evacuation of all Hezbollah operatives from the South Litani Sector".

Lebanon's Litani River runs around 30 kilometres (20 miles) north of the border.

Israel's Defence Minister Israel Katz said earlier Thursday that his country's army will "at this stage, continue its fire and ground operations, remain in the security zone... and without the return of the population, while continuing to dismantle terrorist infrastructure".

Israeli forces retain the "freedom of action, with American backing, to strike in Beirut in response to fire on Israeli communities and territory", Katz added.

Qassem said that Hezbollah pulling back would amount to "surrender and defeat".

"As long as the aggression continues, we will confront it with all our might," he said.