MANILA, Oct 9 — Jailed Philippine human rights campaigner Leila de Lima was briefly taken hostage today during an attempted breakout by three inmates who were shot dead by police, authorities said.

The incident happened at the national police headquarters, where de Lima, a former senator, has been held for more than five years with other high-profile detainees.

One police officer was stabbed before another officer shot dead two of the inmates, police said in a statement.

The third prisoner ran to de Lima's cell and briefly held the 63-year-old hostage before he was also shot dead.

Police said de Lima was not hurt and that the situation inside the detention facility had "returned to normal". An investigation was under way.

Police chief General Rodolfo Azurin told local radio station DZBB that de Lima did not appear to have been the target.

"They saw her as an ideal cover. Their intention really was to escape," he said.

De Lima was unhurt, Boni Tacardon, her lawyer, confirmed to AFP.

"She was brought to the hospital for the standard medical check-up," Tacardon said.

"But based on the information given to us by our staff who's with the senator now, she appears OK."

De Lima has been an outspoken critic of former president Rodrigo Duterte and his deadly drug war.

She has been behind bars since 2017 on drug trafficking charges that she and human rights groups have called a mockery of justice and payback for going after Duterte.

Since President Ferdinand Marcos Jr took power in June, there have been renewed calls from diplomats and rights defenders for de Lima to be released.

The latest incident underscored the need for her to be "freed immediately", said Carlos Conde of Human Rights Watch.

Before her arrest on February 24, 2017, de Lima had spent a decade investigating "death squad" killings allegedly orchestrated by Duterte during his time as Davao City mayor and in the early days of his presidency.

She conducted the probes while serving as the nation's human rights commissioner, then from 2010 to 2015 as justice secretary in the Benigno Aquino administration that preceded Duterte's rule.

De Lima won a Senate seat in 2016, becoming one of the few opposition voices as the populist Duterte enjoyed a landslide win.

But Duterte then accused her of running a drug trafficking ring with criminals inside the nation's biggest prison while she was justice secretary. — AFP