The Israeli army says 21 of its soldiers have been killed in Gaza - the deadliest day for Israeli forces since the start of their ground operation.

A spokesman for the Israel Defense Forces (IDF), Daniel Hagari, said it is thought a rocket-propelled grenade hit a tank near two buildings they were in.bb

He said the buildings exploded probably as result of mines that Israeli forces had placed there to demolish them.

The IDF says it is still investigating the details of the incident.

The incident took place in central Gaza, close to the kibbutz of Kissufim on the Israeli side of the border, at around 16:00 (14:00 GMT) on Monday, Mr Hagari said.

He said the soldiers, most of whom were reservists, were involved in an operation to allow for residents of southern Israel to safely return to their homes after tens of thousands were evacuated after the Hamas attack on 7 October.

Israeli President Isaac Herzog wrote on X, formerly Twitter, that it had been an "unbearably difficult morning" learning about the extent of the death toll.

"On behalf of the entire nation, I console the families and pray for the healing of the wounded," he said.

Israel launched the war with the declared aim of destroying Hamas after waves of its gunmen killed 1,300 people - mostly civilians - and took about 250 others hostage in the unprecedented attack.

At least 25,295 people - mainly woman and children - have been killed in the Israeli military campaign in Gaza since then, according to the Hamas-run health ministry.