The Israeli military said on Saturday it had struck "two terrorist cells" and a Hezbollah post in response to attempted firing from Lebanon as cross-border shelling continued while Israel fights Hamas in Gaza.

The latest skirmishes came a day after Hezbollah chief Hassan Nasrallah warned that the war between Israel and Hamas could turn into a regional conflict if Israel pushed on with its offensive in the Palestinian territory.

"In response to two terrorist cells attempting to fire from Lebanon toward Israeli territory, the IDF (army) struck the cells and a Hezbollah observation post," a military statement said.

It said it had also responded to mortar fire from Lebanon into northern Israel, where no casualties were reported.

Since October 7, Israel has been engaged in a fierce war with Gaza rulers Hamas after the Palestinian militant group carried out a deadly attack in southern Israel that killed 1,400 people, mainly civilians, according to Israeli officials.

Israel has retaliated with relentless strikes and a ground invasion of Gaza, where more than 9,200 people, also mostly civilians, have been killed according to the health ministry in the Hamas-run territory.

The Lebanon-Israel border has also been a scene of regular cross-border shelling over the past month, with firing between the Israeli military on one side and the powerful movement Hezbollah and its allies on the other.

In his first speech since the Israel-Hamas war broke out four weeks ago, Nasrallah warned that "all options" were open for an expansion of the conflict to Lebanon as he blamed the United States for the war in Gaza.

"America is entirely responsible for the ongoing war on Gaza and its people, and Israel is simply a tool of execution," Nasrallah said in a televised broadcast, calling the conflict "decisive".

"Whoever wants to prevent a regional war -- and this is addressed to the Americans -- must quickly stop the aggression on Gaza," he said.