Josep Borrell warns that the killing of a Hamas leader in Lebanon could lead to an escalation of the Israel-Hamas war.

“I believe that we have learned in these 30 years that the solution has to be imposed from outside because the two parties will never be able to reach an agreement,” Borrell said at an event in Lisbon, Portugal, on Wednesday.

“If this tragedy doesn’t end soon, the entire Middle East might end up in flames”, he said.

Israel has bombarded the besieged Gaza Strip since October 7, when Hamas fighters from the Palestinian territory stormed into southern Israel, killing around 1,200 people, and taking around 240 others hostage, according to Israeli officials.

In response to the Hamas attack, Israel declared war, launched a devastating bombardment of Gaza and later ordered a ground invasion that has left much of the territory in ruins. More than 22,000 people, mostly women and children, have been killed in the Israeli assault, according to Palestinian authorities.

The war reached the Lebanese capital Beirut on Tuesday, when a senior Hamas official was killed in a blast. Hamas said its deputy leader, Saleh al-Arouri, was assassinated in an Israeli drone attack.

Israel has neither confirmed nor denied that it killed al-Arouri. Army spokesperson Daniel Hagari said forces were in a high state of readiness and prepared for any scenario.

Hamas politburo member Husam Badran said in a eulogy for al-Arouri, “We say to the criminal occupation [Israel] that the battle between us is open.”

Israel had previously accused al-Arouri of orchestrating attacks on its citizens. A Hamas official said al-Arouri was “at the heart of negotiations” conducted by Qatar and Egypt over the release of hostages held by armed groups in Gaza.

Lebanese Prime Minister Najib Mikati said the death of al-Arouri on Lebanese territory aims to “draw Lebanon” deeper into the war, as the Lebanese armed group, Hezbollah, has traded near-daily fire with Israeli forces since the war began on October 7.

“What happened yesterday with the death of one of the leaders of Hamas is yet another factor that could push the conflict to escalate,” Borrell said.

Hezbollah chief Sayyed Hassan Nasrallah is due to make a speech in Beirut later on Wednesday after he previously warned Israel against carrying out assassinations on Lebanese soil and promised a “severe reaction”.

The United Nations peacekeeping mission in Lebanon warned that any escalation “could have devastating consequences for people on both sides of the border”.

Borrell added that he is planning to visit the Middle East, including Lebanon, to “explore ways out” of the war and would present to EU member states a proposal to create a mission in the Red Sea.

Yemen’s Houthis have been targeting vessels in the Red Sea since October in what they say are acts of solidarity with Palestinians in Gaza.

Several shipping lines have suspended operations through the Red Sea due to the attacks and have changed routes to take the longer journey around Africa instead.