JERUSALEM (AP) -- Gaza's fragile ceasefire faced its first major test Sunday as Israeli forces launched a wave of deadly strikes, saying Hamas militants had killed two soldiers, and an Israeli security official said the transfer of aid into the territory was halted.

The military later said it resumed enforcing the ceasefire, and the official confirmed that aid deliveries would resume Monday. The official spoke on condition of anonymity because he's not authorized to discuss the issue with the media.

A little over a week has passed since the start of the U.S.-proposed ceasefire aimed at ending two years of war. U.S. President Donald Trump said the ceasefire remained in place and "we want to make sure it's going to be very peaceful."

He told reporters aboard Air Force One on Sunday that Hamas has been "quite rambunctious" and "they've been doing some shooting." He suggested that the violence might be the fault of "rebels" within the organization rather than its leadership.

"It's going to be handled toughly but properly," he said. Trump did not say whether he thought the Israeli strikes were justified, saying "it's under review."

Vice President JD Vance said Sunday that he may visit Israel in the coming days.

"We're trying to figure it out," he told reporters, saying the administration wants to "go and check on how things are going." Regarding the ceasefire, he said that "there's going to be fits and starts."

Health officials said at least 36 Palestinians were killed across Gaza, including children. Israel's military said it struck dozens of Hamas targets after its troops came under fire.

A senior Egyptian official involved in the ceasefire negotiations said "round-the-clock" contacts were underway to de-escalate the situation. The official spoke on condition of anonymity because he wasn't authorized to speak to reporters.

Israeli Prime Minister Benjamin Netanyahu directed the military to take "strong action" against any ceasefire violations but didn't threaten to return to war.

Israel's military said militants had fired at troops in areas of Rafah city that are Israeli-controlled according to agreed-upon ceasefire lines.

Hamas, which continued to accuse Israel of multiple ceasefire violations, said communication with its remaining units in Rafah had been cut off for months and "we are not responsible for any incidents occurring in those areas."

Palestinians feared war would return to the famine-stricken territory where Israel cut off aid for over two months earlier this year after ending the previous ceasefire.

"It will be a nightmare," said Mahmoud Hashim, a father of five from Gaza City, who appealed to U.S. President Donald Trump and other mediators to act.

Al-Awda hospital said it received 24 bodies from several Israeli strikes in the Nuseirat and Bureij camps in central Gaza.

An airstrike on a makeshift coffeehouse in Zawaida town in central Gaza killed at least six Palestinians, according to Gaza's Health Ministry, part of the Hamas-run government. A strike in Beit Lahiya in the north killed two men, according to Shifa hospital.

Another strike hit a tent in the Muwasi area of Khan Younis in the south, killing at least four people, including a woman and two children, according to Nasser Hospital.

"Where is peace?" said Khadijeh abu-Nofal in Khan Younis, as hospital workers treated wounded children. She accompanied a young woman hurt by shrapnel.

Israel identified the remains of two hostages released by Hamas overnight: Ronen Engel, a father from Kibbutz Nir Oz, and Sonthaya Oakkharasri, a Thai agricultural worker from Kibbutz Be'eri.

Both were believed to have been killed during the Hamas-led attack on southern Israel on Oct. 7, 2023, which sparked the war. Engel's wife, Karina, and two of his three children were kidnapped and released in a November 2023 ceasefire.

Hamas in the past week has handed over the remains of 12 hostages.

Its armed wing, the Qassam Brigades, said it found the body of another hostage and would return it Sunday "if circumstances in the field" allowed. It warned that any escalation by Israel would hamper search efforts.

Israel on Saturday pressed Hamas to fulfill its ceasefire role of returning the remains of all 28 deceased hostages, saying the Rafah border crossing between Gaza and Egypt would stay closed "until further notice." It was the only crossing not controlled by Israel before the war.

Hamas says the war's devastation and Israeli military control of certain areas have slowed the handover. Israel believes Hamas has access to more bodies than it has returned.

Israel has released 150 bodies of Palestinians back to Gaza, including 15 on Sunday, according to Gaza's Health Ministry. Israel has neither identified the bodies nor said how they died. The ministry posts photos of bodies on its website to help families attempting to locate loved ones. Some are decomposed and blackened. Some are missing limbs and teeth.

Only 25 bodies have been identified, the Health Ministry said.

Israel and Hamas earlier exchanged 20 living hostages for more than 1,900 Palestinian prisoners and detainees.

A Hamas delegation led by chief negotiator Khalil al-Hayya arrived in Cairo to follow up the implementation of the ceasefire deal with mediators and other Palestinian groups.

The next stages are expected to focus on disarming Hamas, Israeli withdrawal from additional areas it controls in Gaza, and future governance of the devastated territory. The U.S. plan proposes the establishment of an internationally backed authority.

Hamas spokesman Hazem Kassem said late Saturday that the group has begun discussions to "solidify its positions." He reiterated that Hamas won't be part of the ruling authority in a postwar Gaza, and called for the prompt establishment of a body of Palestinian technocrats to run day-to-day affairs.

For now, "government agencies in Gaza continue to perform their duties, as the (power) vacuum is very dangerous," he said.

The Israel-Hamas war has killed more than 68,000 Palestinians, according to Gaza's Health Ministry, which doesn't distinguish between civilians and combatants in its count. The ministry maintains detailed casualty records that are seen as generally reliable by U.N. agencies and independent experts. Israel has disputed them without providing its own toll.

Thousands more people are missing, according to the Red Cross.

Hamas-led militants killed around 1,200 people, mostly civilians, and abducted 251 people in the attack that sparked the war.

Renewed fighting tests Gaza ceasefire and Israel briefly halts aid