MANILA, PHILIPPINES -- Human rights activists pressed their call Monday for the immediate release of a former Philippine opposition senator after she was taken hostage in a rampage by three Muslim militants in a failed attempt to escape from a maximum-security jail.

Police killed three Islamic State group-linked militants behind Sunday's violence in which a police officer was stabbed and former Sen. Leila de Lima briefly taken hostage. The militants tried to escape from the jail for high-profile inmates at the national police headquarters in metropolitan Manila, police said.

National police chief Gen. Rodolfo Azurin Jr. acknowledged there were security lapses in the detention centre and said its commander has been removed as part of an investigation.

Amnesty International and Human Rights Watch separately expressed deep alarm over the violence and the hostage-taking of de Lima. The groups calls for her immediate release.

"That she has had to endure this traumatizing and frightening experience on top of being arbitrarily detained for over five years now is the height of outrage, negligence and injustice," Amnesty International Philippine director Butch Olano said.

About two dozen supporters held a protest for de Lima, who was brought to a metropolitan Manila trial court Monday for a hearing, which was postponed.

"We condemned what happened yesterday," said protester Charito del Carmen. "It's painful for us because if she got killed what would happen to the fight for justice that we've been waging for her?"

One of the three inmates stabbed a police officer who was delivering breakfast after dawn in an open area, where inmates can exercise outdoors. A guard in a sentry tower fired warning shots then shot and killed two of the prisoners when they refused to yield, police said.

The third inmate ran to de Lima's cell and briefly held her hostage, Azurin said.

De Lima, 63, told investigators the hostage-taker tied her hands and feet, blindfolded her and pressed a pointed weapon to her chest and demanded access to journalists and a military aircraft to take him to southern Sulu province, where the Muslim militant group Abu Sayyaf has long had a presence.

The man constantly threatened to kill her until he was gunned down by a police negotiator, she told investigators.

Following the jail violence, Filibon Tacardon said he and other de Lima lawyers were hoping the court would now grant her appeal for bail. There have also been appeals to place de Lima under house arrest.

De Lima has been detained since 2017 on drug charges she says were fabricated by former president Rodrigo Duterte and his officials in an attempt to muzzle her criticism of his deadly crackdown on illegal drugs. It left thousands of mostly petty suspects dead and sparked an International Criminal Court investigation as a possible crime against humanity.

She has been cleared in one of three cases, and at least two witnesses have retracted their allegations against her.

Duterte, who has insisted on de Lima's guilt, stepped down from office on June 30 at the end of his turbulent six-year term.

Newly elected President Ferdinand Marcos Jr. talked to de Lima, who was confined in a hospital, by telephone and asked if she wanted to be transferred to another detention site but she rejected the offer, Azurin said.

Even before the jail violence, the European Union Parliament, some American legislators and UN human rights watchdogs have demanded that de Lima be freed immediately.

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Associated Press journalist Aaron Favila contributed to this report.