At least 30 people were killed in an Israeli air strike on a United Nations school in central Gaza where displaced Palestinians were sheltering, local health officials said.

Among the dead were 23 women and children.

The Israel Defense Forces (IDF) said a “precision strike” had targeted a Hamas compound inside the Al-Sardi school, run by the UN agency for Palestinian refugees (UNRWA).

It said “a number of steps” were taken to reduce harming civilians, including aerial surveillance and “additional intelligence information”.

The strike came as Israel expands its operations across the Gaza Strip while senior regional and US officials struggle to help negotiate a ceasefire plan acceptable to both Israel’s government and Hamas.

Earlier this week, the Israeli military announced a new ground and air assault in central Gaza, targeting Hamas militants who have reemerged in areas that were previously cleared.

The IDF revealed on Wednesday that it had also located and destroyed a major Hamas tunnel in Rafah in southern Gaza, next to the border crossing with Egypt, which it alleged was used by the terror group to smuggle weapons into the Strip.

According to an Axios report, the IDF said the Al-Sardi compound was targeted as Hamas and Islamic Jihad militants who belonged to the elite Nukhba Forces and who took part in the October 7 attacks were operating there.

Witnesses to the pre-dawn strike and hospital officials confirmed multiple civilian casualties among refugees who were bunkered down after previously fleeing Israeli offensives and bombardment in northern Gaza.

Ayman Rashed, a man displaced from Gaza City who had taken refuge at the school, told the Associated Press that the missiles hit classrooms on the second and third floor where families were sleeping.

He said he helped carry out five dead, including an old man and two children, one with his head shattered open.

“It was dark, with no electricity, and we struggled to get out the victims,” Mr Rashed said.

Hamas has denied that the school contained a hidden command post.

Juliette Touma, UNRWA’s communications director, said its schools or premises had never been used for “military or fighting purposes”.

The strike will add to mounting international criticism over the rising toll of civilian casualties in Gaza in the eight-month war.

At least 45 people were killed in a strike on a tent camp in Rafah last month, when the IDF was also pursuing Hamas members.

On Wednesday, Human Rights Watch accused Israel of using white phosphorus incendiary shells on residential buildings in at least five towns and villages in conflict-hit southern Lebanon, possibly causing “respiratory damage” among civilians and violating international law.

The Israeli military denied the use of the chemical to target civilians and said it was only deployed as a smokescreen. It said it continued to uphold international law regarding munitions.