Warning: this story contains a description of alleged sexual abuse.

Israeli far-right protesters broke into an army base in a show of support for soldiers accused of severely mistreating a Palestinian prisoner there.

Large crowds gathered outside the Sde Teiman compound after Israeli military police entered it to detain the reservists, who are now subject to an official investigation.

Prime Minister Benjamin Netanyahu released a statement strongly condemning the incident and calling for “an immediate calming of passions”.

Protesters also broke into a second military base, where the reservists were taken for questioning, but a police spokeswoman said officers were able to clear it.

Sde Teiman, near Beersheba in southern Israel, has for months been at the centre of reports of serious abuses against Gazan detainees.

According to local media reports, at least nine Israeli soldiers at the base are accused of abusing the Palestinian detainee, a suspected Hamas fighter who was captured in Gaza.

He is said to have been hospitalised after what Israeli media reports describe as serious sexual abuse and injuries to his anus that left him unable to walk.

The Israeli military said its advocate general had ordered an inquiry “following suspected substantial abuse of a detainee”.

On Monday dozens of protesters, including far-right MPs from Israel’s governing coalition, burst through the base’s gate as others tried to scale the fence, chanting “we will not abandon our friends, certainly not for terrorists”.

Some soldiers at the base reportedly used pepper spray against the military police personnel who arrived to detain the reservists.

Israeli military Chief of Staff Lt Gen Herzi Halevi said the break-in at Sde Tieman was “extremely serious and against the law”.

“We are in the midst of a war, and actions of this type endanger the security of the state,” he said.

“I strongly condemn the incident, and we are working to restore order at the base.”

Demonstrators also entered the Beit Lid military base in central Israel where the accused reservists were taken for questioning.

Defence Minister, Yoav Gallant, said the investigation into the soldiers’ conduct must be allowed to continue, adding “even in times of anger, the law applies to everyone”.

However some Israeli politicians have condemned the arrest of the reservists. Itamar Ben-Gvir, the far-right national security minister, called their detention “nothing less than shameful”.

Since the 7 October Hamas attack, Israeli authorities have rounded up and held thousands of Palestinians, often without legal representation.

The BBC has previously spoken to medical workers at a field hospital set up in Sde Teiman, who alleged that detainees have been blindfolded, permanently shackled to their beds, and made to wear nappies rather than having access to a toilet.

Last month, Israel’s Haaretz newspaper published allegations made by a doctor at Sde Teiman that leg amputations had been carried out on two prisoners, because of cuffing injuries. The BBC has not independently verified the claims.

Detainees there have told journalists and United Nations officials that they were beaten and attacked. The Israeli Defence Forces (IDF) have denied systematic abuse.

Many Gazans detained by Israel’s army are released without charge after interrogation. Amnesty International this month called on Israel to end the indefinite detention of Gaza Palestinians and what it called “rampant torture” in its prisons.