"What we have learned over the last 30 years, and what we are learning now with the tragedy experienced in Gaza, is that the solution must be imposed from outside," Borrell told diplomats in Portugal.

"Peace will only be achieved in a lasting manner if the international community gets involved intensely to achieve it and imposes a solution," he said, pointing to the United States, Europe and Arab countries.

Borrell warned that a strike in Beirut on Tuesday that killed a senior Hamas leader was "an additional factor that can cause an escalation of the conflict".

The EU's top diplomat said he had planned to travel to Lebanon on Thursday but the trip might be cancelled due to security concerns.

Although Israel did not claim responsibility, it is widely assumed to be behind the killing of Saleh al-Aruri, 57, the political number two of its enemy Hamas and one of the founders of the Islamist group's military wing.

Israel has vowed to destroy Hamas and has launched a relentless military campaign in Gaza that has claimed over 22,000 lives, two-thirds of them women and children, according to the territory's health ministry.

The Israeli war on Gaza started after the October 7 Al-Aqsa Flood operation by Hamas on Israel that killed around 1,140 people, most of them civilians, according to an AFP tally based on official Israeli figures.

Militants also took around 250 catives back to Gaza, 129 of whom remain in captivity, according to Israeli figures.