"A ceasefire that is sustained by a meaningful peace process ... is the only way to break the cycle of violence, of hatred, of misery," said UN refugee chief Filippo Grandi.

Speaking at the start of the UNHCR refugee agency's annual executive committee meeting in Geneva, he insisted that only a ceasefire could "stem the tide to a major regional war with global implications".

His comments came amid escalating Israeli attacks targeting Hezbollah militants in Lebanon, where more than 1,300 people have been killed and a million displaced since late September, according to Lebanese officials.

Hezbollah started firing into northern Israel a year ago to support Hamas following its deadly October 7 attacks that sparked the devastating war in Gaza.

The near-daily exchange of fire led to the displacement of tens of thousands of people on both sides of the border even before the escalation last month, when Israeli Prime Minister Benjamin Netanyahu vowed to crush Hezbollah to allow Israelis displaced by the violence to return home.

"You will have seen the images and heard the numbers; hundreds of thousands of displaced inside Lebanon, seeking reprieve from Israeli airstrikes," Grandi said.

"Once again, the distinction made between civilians and combatants has almost become meaningless."

The UN high commissioner for refugees, who has just returned from Lebanon and neighbouring Syria, slammed attacks impacting humanitarian workers.

Grandi paid tribute to two UNHCR workers killed in an Israeli airstrike in Lebanon last month, and also highlighted the 226 staff working for the UN agency for Palestinian refugees, UNRWA, killed in Gaza in the past year.

"We cannot accept that lives of humanitarians are dismissed as mere collateral damage, or worse, maligned as somehow culpable or complicit," he said.

Despite the attacks, he stressed that the United Nations would "stay and deliver".

Grandi highlighted the plight of Syrian refugees who had fled the civil war in their country to seek refuge in Lebanon, only to find themselves "uprooted again".

Many have crossed back to Syria along with Lebanese and others fleeing the Israeli airstrikes.

UNHCR says 276,000 people have crossed the border so far -- 70 percent of them Syrian nationals. Lebanese authorities put the number at over 400,000.

© Agence France-Presse