The killing of Hamas deputy leader Saleh al-Arouri by an Israeli drone strike in Lebanon's capital Beirut has raised the potential risk of the war in Gaza spreading well beyond the Palestinian enclave.
Arouri, 57, was the first senior Hamas political leader to be assassinated since Israel launched a shattering air and ground offensive against the group almost three months ago after its shock assault and rampage into Israeli towns.
Israel has long accused Arouri of lethal attacks on its citizens, but a Hamas official said he was also "at the heart of negotiations" conducted by Qatar and Egypt over the outcome of the Gaza war and the release of Hamas-held Israeli hostages.
Israel neither confirmed nor denied carrying out the killing, but its military spokesperson Rear Admiral Daniel Hagari said Israeli forces were in a high state of readiness and prepared for any scenario.
Since the war broke out on October 7, that killed 1,200 people, more than 22,000 Palestinians have died in Gaza.
Israel has vowed to keep fighting until it has wiped out Hamas and secures the release of its hostages.
US President Donald Trump and Iran threatened to escalate their war by attacking energy and desalination facilities in the Gulf, a potential widening of hostilities that could deepen a regional crisis and add to concerns in global markets.
An Israeli airstrike on a police vehicle on Sunday killed three people in the middle of the Nuseirat camp in the central Gaza Strip, health officials said, hours after another person was killed in a strike on northern Gaza.
The Strait of Hormuz remains open to all shipping except vessels linked to "Iran's enemies", Iran's representative to the UN maritime agency was quoted as saying in Iranian media reports published on Sunday.
The Gulf Cooperation Council (GCC) has renewed its condemnation of continued Iranian attacks on member states, including the targeting of infrastructure and oil facilities, in flagrant violation of international law and a direct threat to regional security, stability and the safety of global energy supplies.