Hamas is claiming Israel has killed one its highest-ranking leaders in a drone strike in Lebanon’s capital of Beirut.

Six people are said to have died during the brazen attack on a Hamas office in a southern suburb of the Lebanese city.

Among them was Hamas deputy leader Saleh al-Arouri – a member of the politburo based abroad and a co-founder of Hamas’ military wing, the Qassam Brigades.

He is the most senior member of Hamas killed since the militant group’s October 7 incursion into Israel.

The drone attack underlines the risk of the Israel-Hamas war spreading well beyond the Gaza Strip.

Lebanon’s heavily armed Hezbollah group, a Hamas ally, has exchanged near-daily fire with Israel across Lebanon’s southern border since the Gaza war erupted in early October.

Lebanon’s caretaker prime minister Najib Mikati condemned the drone blast as a “new Israeli crime” and said it was an attempt to pull Lebanon into war.

Mark Regev, an adviser to Israeli Prime Minister Benjamin Netanyahu, told MSNBC TV that Israel “has not taken responsibility for this attack.

“But whoever did it, it must be clear – this was not an attack on the Lebanese state … Whoever did this did a surgical strike against the Hamas leadership”.

Israel had accused Arouri of supervising and ordering Hamas attacks in the Israel-occupied West Bank in support of militants fighting Israel’s devastating air and ground offensive in Gaza.

“I am waiting for martyrdom (death) and I think I have lived too long,” Arouri said in August 2023, alluding to Israeli threats to eliminate Hamas leaders whether in Gaza or abroad.

The war was triggered by a shock cross-border Hamas assault on Israeli towns on October 7 that Israel says killed 1200 people with some 240 hostages spirited back to Gaza – the bloodiest single day in the Jewish state’s 75-year history.

The Gaza health ministry said 207 people had been killed in the past 24 hours, bringing the total recorded Palestinian death toll to 22,185 in nearly three months of war in Gaza – the most lethal chapter of the decades-long Israel-Palestinian conflict.

Hundreds of Palestinians took to the streets of Ramallah in the West Bank to condemn Arouri’s killing, chanting, “Revenge, revenge, Qassam!”.

Israeli Defence Minister Yoav Gallant said operations around Khan Younis, southern Gaza’s main city, concentrated on areas above the tunnel network where Hamas leaders were believed to be hiding.

“We are reaching them all ways. There already is engagement and there are [Israeli] hostages there too, sadly,” he told troops in Gaza in footage shown on Israeli television.

“This will continue as high-intensity efforts in the heart of Khan Younis,” he said.

Civilian casualties have mounted in south Gaza as the brunt of Israel’s offensive has shifted there from the north.

Israel says it tries to avoid harm to civilians but blames Hamas for embedding fighters among them, an accusation the militant group denies.

The US, Israel’s main supporter, has urged it to rein in its air and ground blitz – which has demolished vast tracts of densely populated Gaza – in favour of more targeted strikes focusing on Hamas leaders.

Israel has announced plans to pull back some troops, hinting at a new phase in the war amid a rising global outcry over the plight of Gaza civilians although it also warned its offensive has many months to run.

Shortly before Arouri’s killing, Hamas’ paramount leader Ismail Haniyeh, who is also based outside Gaza, said the movement had delivered its response to an Egyptian-Qatari ceasefire proposal.

He reiterated that Hamas’ conditions entailed “a complete cessation” of Israel’s offensive in exchange for further releases of hostages.

Israel believes 129 hostages remain in Gaza after some were released during a brief truce in late November and others were killed during air strikes and rescue or escape attempts.

-with AAP