An Israeli military official said on Sunday Hamas had carried out multiple attacks against Israeli forces inside Gaza, including a rocket-propelled grenade attack and a sniper attack against Israeli soldiers.
"Both of the incidents happened in an Israeli-controlled area ...This is a bold violation of the ceasefire," the official said.
Senior Hamas official Izzat Al Risheq said on Sunday the Palestinian militant group remained committed to the ceasefire, which he accused Israel of repeatedly violating.
Neither Al Risheq nor the Israeli military official made any mention of the reported Israeli strikes in Gaza.
The government media office in Gaza said on Saturday Israel had committed 47 violations after the ceasefire deal, leaving 38 dead and 143 wounded.
The impact of the Israeli strikes on Sunday, the most serious test since an already fragile ceasefire took effect on October 11, was not immediately clear.
The Israeli government and Hamas have been accusing each other of violations of the ceasefire for days, with Israeli Prime Minister Bejamin Netanyahu saying the Rafah border crossing between Gaza and Egypt will remain closed until further notice.
Netanyahu's statement came shortly after the Palestinian embassy in Egypt announced the Rafah crossing, the main gateway for Gazans to leave and enter the enclave, would reopen on Monday for entry into Gaza.
The US State Department said it had received "credible reports" indicating Hamas would violate the pact.
"Should Hamas proceed with this attack, measures will be taken to protect the people of Gaza and preserve the integrity of the ceasefire," the department said in a statement late on Saturday, without providing details.
Hamas denied on Sunday accusations of an "imminent attack" or a "violation" of the ceasefire.
It accused Israeli authorities of forming, arming and funding "criminal gangs" that carried out murders and kidnappings and aided looting.
Rafah has largely been shut since May 2024.
The ceasefire deal also includes the ramping up of aid into the enclave, where hundreds of thousands of people were determined in August to be affected by famine, according to the IPC global hunger monitor.
Israel and Hamas have been engaged in a dispute over the return of the bodies of deceased hostages.
Israel demanded that Hamas fulfil its obligations in turning over the remaining bodies of all 28 hostages.
Hamas has returned all 20 live hostages and 12 of the deceased but said the process needed effort and special equipment to recover corpses buried under rubble.
Formidable obstacles to Trump's plan to end the war remain.
Key questions of Hamas disarming, the governance of Gaza, the make-up of an international "stabilisation force" and moves towards the creation of a Palestinian state have yet to be resolved.
The US embassy in Jerusalem did not immediately respond to a request for comment.
