Israel said it reopened the Kerem Shalom border crossing to humanitarian aid for Gaza Wednesday, four days after closing it in response to a rocket attack that killed four soldiers.

"Trucks from Egypt carrying humanitarian aid, including food, water, shelter equipment, medicine and medical equipment donated by the international community are already arriving at the crossing," the army said in a joint statement with COGAT, the defence ministry body that oversees Palestinian civil affairs.

The supplies will be transferred to the Gaza side of the crossing after undergoing inspection, the statement released at around 9:15 am (0615 GMT) said.

The UN agency for Palestinian refugees however said the Kerem Shalom crossing remained closed.

"The crossing is still not open," UNRWA spokeswoman Juliette Touma told AFP at about 10:40 am (0740 GMT).

The military said the Erez border crossing between Israel and northern Gaza was also open for aid deliveries into the Palestinian territory.

The Kerem Shalom crossing was closed after a Hamas rocket attack killed four soldiers and wounded more than a dozen on Sunday.

On Tuesday, Israeli troops seized control of the Palestinian side of the Rafah crossing between Gaza and Egypt after launching an incursion into the eastern sector of the city.

The UNRWA spokeswoman said the Rafah crossing too remained closed.

"We are calling for their reopening. We normally get fuel through Rafah not Karem (Shalom)," Touma said.

"There’s not been humanitarian supplies for the past three days. We have started rationing fuel," she said, adding Gaza needed 300,000 litres (79,250 gallons) of fuel a day for humanitarian purposes.

On Tuesday, UNRWA chief Philippe Lazzarini said the two crossings were a "lifeline" for delivering aid to Gaza.

"Through them we bring critical supplies and fuel for humanitarian use. They need to be reopened without any delay," he said on X, formerly Twitter.

Israel's staunchest ally the United States too called for the reopening of the two crossings.