Israel was checking on Monday if Hamas's second-highest military leader died in an air strike, media said, as talks stumbled to secure a ceasefire in the Gaza war to coincide with the Muslim holy month of Ramadan.

If his death is confirmed, Marwan Issa would be the highest-ranking official from the Islamist militant movement taken out by Israel in the more than five-month war that has pulverised the Palestinian enclave and killed thousands.

Israeli Army Radio said Israel had bombed the Al-Nusseirat camp in central Gaza on Saturday night, where it had intelligence about the location of Issa, second-in-command of Hamas's military wing the Izz el-Deen al-Qassam Brigades.

The attack killed five people, the report said.

Israeli newspaper Haaretz reported that Israel was checking if the fatalities included Issa.

Neither the Israeli military nor Hamas officials immediately commented on the media reports.

On Sunday, in a statement rounding up operations from the previous 24 hours, Israel said its forces had killed militants in central Gaza but did not mention the camp.

Issa is high on Israel's most wanted list, together with military wing head Mohammed Deif and Hamas's Gaza leader Yahya Sinwar, who are believed to have masterminded the Oct. 7 attack that triggered the conflict.

Fighters from Hamas, which controls Gaza, killed 1,200 people in a rampage into southern Israel and took 253 hostages, by Israeli tallies. The ensuing war killed more than 31,000 Palestinians and injured nearly 73,000, according to Gaza authorities, as well as obliterating infrastructure and causing widespread hunger.

Issa's death, if confirmed, could also complicate efforts to secure a ceasefire and the release of hostages, although Israel says talks are ongoing through Egyptian and Qatari mediators.

Israel's intelligence agency Mossad said at the weekend that both sides were seeking to narrow gaps and reach agreements.

Hamas blames Israel for refusing to give guarantees to end the war and withdraw troops. Israel wants a temporary truce to allow an exchange of hostages, but has said it will not stop its war until it has defeated Hamas.

SIXTEEN DIE IN HOUSE

Negotiators had wanted a halt in hostilities for Ramadan, which began on Monday.

But in the early hours, an Israeli air strike on a house in Gaza City killed 16 people and wounded several others, Palestinian health officials said.

The strike, around dawn in Zeitoun, one of Gaza City's oldest neighbourhoods, hit the house of the Abu Shammala family, killing those inside, according to medics. There was no immediate Israeli comment on that strike.

In central Gaza, the Israeli military said its forces had killed around 15 militants in close combat and air strikes. Commandos in Khan Younis, where much of Israel's military operation has been focused in recent weeks, targeted sites it said were used by Hamas militants, the military said.

Elsewhere around the region, pro-Palestinian groups continued to make their presence felt. Lebanon's Hezbollah said it launched a multi-drone attack on an outpost in the Israeli-occupied Golan Heights, while two other incidents were reported in Red Sea waters where Yemen's Houthis have been attacking ships.

The conflict has displaced most of Gaza's 2.3 million people, with many cramped into makeshift tents in southern Rafah city, lacking food and basic medical supplies.

The United Nations estimates about a quarter of the population risk starvation and the trickle of aid is barely scratching the surface of daily needs. Aid agencies are now focusing their efforts on delivering aid via sea.

A government source in Cyprus said a vessel carrying some 200 tonnes of aid was scheduled to set sail on Monday, while the U.S. military said its General Frank S. Besson ship was also en route to provide humanitarian relief to Gaza by sea.

In his State of the Union address last week, U.S. President Joe Biden said the U.S. would build a temporary seaport off the Gazan coast to facilitate more aid deliveries.

Senior Hamas official Basem Naim said the water corridor was positive but urged the United States to work to end the war.

"Ensuring all the needs of the population in the Gaza Strip are met is not a favour from anyone. It is a guaranteed right under international humanitarian law even during times of war," Naim told Reuters.

(Reporting by Nidal al-Mughrabi in Cairo and Maayan Lubell in Jerusalem; writing by Sharon Singleton; editing by Andrew Cawthorne)