Since fighting between Hamas militants and Israeli forces began in Gaza, United Nations agencies, rights advocates, officials in the Hamas-run territory, and ex-prisoners interviewed by AFP have all alleged abuses during detention.

Israel's military has said its detention conditions are in line with international law.

"Following suspected substantial abuse of a detainee held in the Sde Teiman detention facility... an investigation was opened," the military said in a statement to AFP, without giving details.

Israeli media, however, reported that the detainee was a Palestinian who had allegedly been abused by some Israeli soldiers at the facility.

Media reports also said eight soldiers had been detained as part of the investigation.

Several Israelis, on hearing of the soldiers' detention, rushed towards the facility in a sign of support, with some even managing to break into it, live footage broadcast by Israeli television networks showed.

Army chief Lieutenant-General Herzi Halevi condemned their action.

"Breaking into a military base and disturbing the order there is severe behaviour that is not acceptable in any way," Halevi said in a statement.

"We are in the midst of a war and actions of this type endanger the security of the state.

"I strongly condemn the incident, and we are working to restore order at the base," he said.

The Sde Teiman facility was set up to detain Palestinians arrested in the Gaza Strip soon after the war there began on October 7 following the attack by Hamas on southern Israel.

The Hamas attack resulted in the deaths of 1,197 people, mostly civilians, according to an AFP tally based on official Israeli figures.

Militants also seized 251 people, 111 of whom are still held in Gaza, including 39 who the military says are dead.

Israel's retaliatory response has killed 39,363 people in Gaza, according to Gaza's health ministry which does not provide details on civilian and militant deaths.

Amnesty International this month called on Israel to end the indefinite detention of Gaza Palestinians and what it called "rampant torture" in its prisons.

Amnesty said it had documented 27 cases of Palestinians, including five women and a 14-year-old boy, who were detained "for up to four and a half months" without being able to contact their families.