Israel carried out its heaviest airstrikes in Gaza in weeks on Saturday, killing 26 people, according to local health authorities.

Despite the tenuous ceasefire agreed between Israel and Palestinian militant group Hamas, Israeli warplanes targeted a Hamas-run police station and on apartments and tents in an area sheltering displaced Palestinians.

Rescue teams were searching for more casualties at the site, said the police, which is run by Hamas in the Gaza Strip.

Another airstrike hit an apartment in Gaza City killing three children and two women, according to officials at Shifa hospital in the city. Seven more were killed in a strike at a tent encampment in Khan Younis further south.

An Israeli military source said the strikes were a response to an incident on Friday when troops identified eight gunmen emerging from a tunnel in Rafah, an area in southern Gaza where Israeli forces are presently deployed under the October ceasefire agreement.

Three of the gunmen were killed by the forces and a fourth, whom the Israeli military described as a key Hamas commander in the area, was arrested.

Trading blame over ceasefire

Israeli fire has killed more than 500 people, most of them civilians according to Gaza health officials, since the US-brokered truce between Palestinian militant group Hamas and Israel took effect in October after two years of war.

Palestinian militants have killed four Israeli soldiers since the truce, according to Israeli authorities.

The two sides have traded blame over truce violations, even as Washington presses them to proceed to the next phases of the ceasefire deal meant to end the conflict for good.

The next phase of US President Donald Trump's plan includes complex issues such as Hamas disarmament, which the group has long rejected, further Israeli withdrawal from Gaza and the deployment of an international peacekeeping force.

Gaza's main gateway, the Rafah border crossing with Egypt that has been largely shut during the war, is expected to reopen on Sunday.