Israeli forces bombarded the Gaza Strip's historic refugee camps in the centre of the enclave and struck Gaza City in the north on Thursday, killing at least 13 people, and tanks pushed deeper into Rafah in the south, health officials and residents said.

One Israeli airstrike killed six people in Zawayda town in central Gaza and two other people were killed in a strike on a house in Bureij camp. An Israeli air strike killed three people in a car in Deir Al-Balah, a city packed with people displaced from elsewhere in Gaza, health officials said.

In Gaza City in the north, medics said two Palestinians were killed in another airstrike.

The Israeli military said in a statement its forces killed two senior Islamic Jihad commanders in two airstrikes in Gaza City, including one whom it said had taken part in the Oct. 7 attack in southern Israel that triggered the Gaza war.

In Rafah, residents said Israeli tanks advanced deeper in the western side of the city and took position on a hilltop there. The Israeli military said forces located several tunnels and killed several gunmen.

The armed wing of militant group Hamas and its allies said they fired mortar bombs at Israeli forces in southwest Rafah on Thursday.

More than a million people had sought shelter in Rafah from fighting further north, but most have scattered again since Israel launched an offensive in and around the city in May.

The fighting has pushed the 60-bed Red Cross field hospital in Rafah to the brink of capacity, the International Committee of the Red Cross (ICRC) said in a statement on Thursday.

"The repeated mass casualty events resulting from the unrelenting hostilities have stretched to breaking point the response capacity of our hospital – and all health facilities in southern Gaza – to care for those with life-threatening injuries," said William Schomburg, head of the ICRC's subdelegation in Gaza.