Israeli airstrikes struck Gaza for a second consecutive day on Sunday, killing at least 18 Palestinians, medics reported. The renewed violence unfolded despite an announcement from U.S. President Donald Trump of a breakthrough in efforts to implement last year's ceasefire agreement.

From dawn, Israeli warplanes targeted Gaza City in the north, the central city of Deir al-Balah, and the southern area of Khan Younis, marking the highest daily death toll in weeks, according to Palestinian health officials.

President Trump's assertion on Thursday, claiming Palestinian Hamas militants and other armed groups had agreed to disarm, had previously raised hopes of a turning point in efforts to end the conflict.

On Sunday, Israel's Energy Minister Eli Cohen, a member of Prime Minister Benjamin Netanyahu's security cabinet, stated the government would offer Hamas an opportunity to disarm, though he expressed "very sceptical" doubts about its likelihood.

Speaking to Israel's Army Radio, Mr Cohen asserted there was no agreement to cease attacks on Gaza, suggesting Israel, which already controls 70 per cent of the enclave, might need to assume full control if Hamas failed to disarm.

"In the deal we signed with the United States, our stance is that Hamas must be dismantled. This is the first thing that must happen," he added.

Later that day, a spokesperson for Mr Netanyahu's office informed Reuters that Israel had conveyed its concerns to the US regarding the disarmament plan.

"The most important concern for Israel is that nothing can happen before Hamas completely and truly disarms ...," said Doron Spielman, a spokesperson for the Israeli prime minister's office.

In Deir al-Balah, strikes claimed at least four lives, according to Palestinian health officials. A separate assault in Mawasi, near Khan Younis, wounded five and ignited several tents, the civil emergency service reported.

Palestinian officials also reported the deaths of a couple and their nine-year-old son in a strike on a Mawasi home.

In Gaza City, medics confirmed another couple and their child perished in an apartment strike, while two further individuals died in a tent near the Egyptian representative mission's office.

Later on Sunday, two more fatalities were reported in the city's eastern Zeitoun neighbourhood. Near Jabalia in northern Gaza, Palestinian officials confirmed one death.

The Israeli military stated that a strike on an apartment in Deir al-Balah had targeted two commanders of Hamas' elite "Nukhba" force.

Strikes in Gaza City and Jabalia also aimed at "military operatives", the military added, though it was still reviewing the situation. A subsequent Israeli airstrike on a car in Gaza City killed at least three Palestinians near Saraya Square, medics reported.

President Trump's 'Board of Peace', the US-led body overseeing the ceasefire, had on Friday published a 15-point roadmap detailing the final steps for implementing the agreement.

Nickolay Mladenov, the Board of Peace's lead envoy for Gaza, noted that the widespread strikes occurred despite efforts by the board and mediators to secure agreement among Palestinian factions on the roadmap for President Trump's plan.

In a post on X, he affirmed he was collaborating with parties, mediators, and regional partners to "de-escalate and create the space for the full implementation of the President's plan". "Achieving a lasting peace is hard but achievable if everyone makes their best efforts," Mr Mladenov stated.

Since a ceasefire was agreed in October, at least 1,230 Palestinians have been killed in Israeli strikes, according to Gaza health authorities. Hamas does not release figures on its combat fatalities. Over the same period, four Israeli soldiers have been killed, Israeli tallies indicate.

Hamas has maintained that Israel must cease its attacks in Gaza and withdraw its troops, in line with other key terms of the ceasefire deal, before it will agree to surrender weapons to a newly designated Palestinian body tasked with governing Gaza. A senior Hamas official stated on Sunday that the group had shown "considerable flexibility", yet accused Israel of attempting to impose a de facto situation on the ground through intensified strikes.

"This escalation, coinciding with progress on the political track, clearly demonstrates that the occupation government is seeking to undermine efforts aimed at ending the war and to impose facts on the ground by force," Basem Naim said in a statement.

Mohammed Dahlan, a former senior Fatah official based in the United Arab Emirates, claimed in a Facebook post that Jared Kushner, President Trump's son-in-law and a senior adviser involved in the US initiative, had informed him he was collaborating with the Israeli side to halt attacks on Gaza. Mr Dahlan added that contacts with the US were ongoing to ensure the agreement's full implementation, stressing that its success now hinged on Israel completely ending its daily attacks on Gaza.

Reuters has sought comment from the US State Department regarding Mr Dahlan's remarks, with no immediate response from Israel.