An Israeli airstrike targeting the top leaders of Yemen's Houthi rebels in August killed the chief of staff of its military, officials said Thursday, further escalating tensions between the group and Israel even as a ceasefire holds in the Gaza Strip.

The Houthis have acknowledged the killing of Maj. Gen. Muhammad Abdul Karim al-Ghamari, who had been sanctioned by the United Nations over his role in the country's decadelong war.

A bomb exploded Thursday on a Syrian Defense Ministry bus in the country's east, killing four soldiers and wounding others, the country's oil minister said.

Israel returned the bodies of 30 Palestinians to Gaza on Thursday, bringing the total number handed over to 120, the Hamas-run health ministry and Nasser Hospital in Khan Yunis said.

Under a ceasefire deal brokered by U.S. President Donald Trump, Israel was to turn over the bodies of 15 Palestinians for every deceased Israeli returned.

Prime Minister Benjamin Netanyahu said Thursday that Israel was "determined" to secure the return  of the remains of all hostages still held in Gaza, vowing that the "fight is not over yet".

"We are determined to secure the return of all hostages," Netanyahu said at a state ceremony at Jerusalem's Mount Herzl military cemetery, marking the October 7, 2023 Hamas attack on Israel that sparked the war.

Israel said Thursday that the date for the opening of the Rafah crossing between Gaza and Egypt would be announced at a later stage, and that aid would not pass through the gateway.

"The date for the opening of the Rafah Crossing for the movement of people only will be announced at a later stage, once the Israeli side, together with the Egyptian side, completes the necessary preparations for the crossing's opening," said a statement from COGAT, the Israeli defense ministry body that oversees civil affairs in the Palestinian territories.

An Israeli group campaigning for the return of all hostages held in Gaza on Thursday demanded that the government delay implementing the next stages of the truce if Hamas fails to return the remaining captives' bodies.

In a statement, the Hostages and Missing Families Forum urged the Israeli government to "immediately halt the implementation of any further stages of the agreement as long as Hamas continues to blatantly violate its obligations regarding the return of all hostages and the remains of the victims".

Syrian interim president Ahmed al-Sharaa will ask Russia to hand over former ruler Bashar al-Assad during his first visit to Moscow on Wednesday, a government official said.

Israel was expected to allow Gaza's sole border crossing to the outside world to reopen Wednesday to allow aid into the devastated territory as part of a U.S.-backed ceasefire deal.

Israeli public broadcaster KAN said the reopening was imminent despite questions over Hamas's ongoing transfer of the remains of deceased hostages, under a swap deal spearheaded by U.S. President Donald Trump after two years of war.

The bodies of 45 Palestinians that had been in Israeli custody were handed over to a Gaza hospital Tuesday, the Nasser Medical Centre said.

Under a ceasefire deal brokered by U.S. President Donald Trump, Israel was to turn over the bodies of 15 Palestinians for every deceased Israeli returned.

The tenuous ceasefire in the two-year Israel-Hamas war was holding Tuesday even as complex issues remained ahead, a day after widespread jubilation over the return to Israel of the last 20 living hostages held in Gaza and the release of hundreds of Palestinian prisoners and detainees in exchange.