A burst of gunfire has rung out in the Philippine Senate, where authorities have tried to arrest a senator who is wanted by the International Criminal Court for a charge of crimes against humanity, an Associated Press journalist and other witnesses say.

It was not immediately clear what set off the gunfire or if there were injuries in the Senate chamber, where Senator Ronald dela Rosa has stayed under the protection of allied senators as Philippine authorities tried to arrest him and possibly turn him over later to the ICC.

The ICC had no immediate comment on the events in Manila.

READ MORE: Trump claims key topic off agenda as 'two superpowers' meet in Beijing

Senate President Alan Cayetano briefly appeared before journalists in the Senate and confirmed that he has been told by the building's security that gunshots were fired, but he did not provide other details and hastily left.

"The emotions are high here," Cayetano said.

"This is the Senate of the Philippines and we are allegedly under attack."

A huge throng of reporters and photo and video journalists, who have been covering the tense developments, were asked to stay in an area on the second floor. Some were later allowed to leave the building after Interior Secretary Juanito Victor Remulla jnr arrived with police officers.

On Monday, the ICC unsealed an arrest warrant for dela Rosa, a former national police chief who first enforced then President Rodrigo Duterte's anti-drug crackdowns, in which thousands of mostly petty suspects were killed.

Originally issued in November, the warrant charges dela Rosa with the crime against humanity of murder of "no less than 32 persons" between July 2016 and the end of April 2018, when he led the national police force under Duterte.

READ MORE: Mum to be charged after sending son to school with hidden device

Dela Rosa, 64, has vowed to fight the ICC arrest order and said that he would seek all legal remedies. He also called on his followers on Wednesday night to gather in the Senate to prevent what he said was his impending arrest.

National Bureau of Investigation agents tried to arrest dela Rosa on Monday, but he managed to dash to the Senate's plenary hall and sought the help of fellow senators. Cayetano said then that he would cite the government agents involved for contempt.

Duterte was arrested in March last year and flown to the ICC's headquarters in The Hague for detention. He remains detained by the ICC in the Netherlands and is facing a trial for alleged crimes against humanity for the killings in his brutal crackdown, in which dela Rosa has been named as one of several co-perpetrators.

"We should not allow another Filipino to be brought to The Hague, the second one after President Duterte," dela Rosa said, addressing his followers in a Facebook message and blaming politics for his predicament.

"This is unacceptable," dela Rosa said.

READ MORE: Paramedic's 'absolute shock, disbelief' as gran Tasered

He said that he was ready to face any allegations before Philippine courts, but he denied condoning extrajudicial killings when he led the police force. Duterte has also made the same denials, although he openly threatened suspected drug dealers with death while he was in office.

Hundreds of police officers have been deployed outside the Senate to maintain order, sparking complaints from dela Rosa and allied senators.

"If I have something to answer for, I will face those in our local courts and not before foreigners," dela Rosa told reporters in the Senate, which took him into "protective custody" on Monday when he reappeared after months of absence.

Five senators called on dela Rosa to surrender to authorities in a proposed resolution, but his allies opposed the move in a heated exchange on Wednesday in the Senate, where 13 of 24 senators friendly to dela Rosa wrested control of its leadership on Monday.

Dela Rosa has been critical of President Ferdinand Marcos jnr but pleaded emotionally before television cameras on Monday for the president not to bring him to The Hague.

Duterte and his daughter, the current vice president, and political allies like dela Rosa have been the harshest critics of Marcos. Vice President Sara Duterte, once a political ally of Marcos, has blamed the president for allowing what she said was "the kidnapping" of her father and his handover to a foreign court.

After winning the presidency in 2016, Duterte designated dela Rosa, a loyal ally, as head of the national police force, which enforced the brutal campaign against illegal drugs.

Dela Rosa also once headed the police force in the southern city of Davao, where Duterte was a long-time mayor and built a political name for his extra tough approach to crimes.

"My role was to lead the war on drugs, and that war on drugs was not meant to annihilate people," dela Rosa said when he was asked about the huge death toll.

"When the lives of police officers came under threat, of course they needed to defend themselves," dela Rosa said.

Duterte withdrew the Philippines in 2019 from the ICC, in a move human rights activists say was aimed at escaping accountability.

The ICC, however, said that it retained jurisdiction over crimes committed when the Philippines was still a member and successfully moved to have him arrested, the first former Asian leader to fall into such disgrace.

NEVER MISS A STORY: Get your breaking news and exclusive stories first by following us across all platforms.

• Download the 9NEWS App here via Apple and Google Play
• Make 9News your preferred source on Google by ticking this box here
• Sign up to our breaking newsletter here

A police officer who fatally Tasered a 95-year-old great-grandmother with dementia could have been ordered to stand down, an inquest has been told.

Then-senior constable Kristian James Samuel White fired his weapon at Clare Nowland after being called to Yallambee Lodge nursing home at Cooma in southern NSW on May 17, 2023.

Then-acting sergeant Jessica Pank said "oh shit" when her 36-year-old partner deployed the stun gun, telling the inquest on Wednesday she did not expect him to pull the trigger.

READ MORE: 'Very decomposed' body confirmed to be triple killer

Pank, now a senior constable, testified she did not have the authority to tell White to re-holster his weapon, because it was his call to make.

But NSW Police operational safety instructor Senior Sergeant William Watt disputed this, saying if he was in that position, he would have steered White away from using the Taser the second he pulled it out.

"Effectively, as soon as I realised somebody had drawn a Taser in that environment, as the senior person there, that's not happening," he said.

Pank said she was not surprised when her partner took out the weapon, saying she thought he was using it to cover her as she tried to take the knife out of Nowland's hand.

Under questioning by Judge Teresa O'Sullivan, she admitted there was no urgency in resolving the situation at the time her partner pulled the trigger.

Pank testified if she had been told White was going to use the Taser, she would have discussed other options.

READ MORE: Bizarre conspiracy theories in Trump's late night Truth Social spree

Elsewhere in her evidence, the officer acknowledged there were alternatives available, including letting Nowland come into the corridor so police could approach her from different angles.

Intensive care paramedic Anna Hofner told the inquest she felt "absolute shock and disbelief" as she witnessed White deploy the stun gun.

"I didn't think the use of a Taser was proportionate to the magnitude of the incident … it seemed excessive," she said.

Emergency services were called to the facility in the early hours of the morning after Nowland grabbed two serrated steak knives from the kitchen and refused to give them up.

During the two-minute and 40-second encounter, White drew his stun gun and pointed it at the great-grandmother for a minute before saying "nah, bugger it" and discharging the weapon at her chest.

AS IT HAPPENED: Chalmers' subtle attack on Hanson in parting shot

The 48-kilogram great-grandmother, who had symptoms of dementia, fell and hit her head.

She did not regain consciousness and died in hospital a week later after a brain bleed.

Watt found the situation confronting White as Nowland stepped towards him was not exceptional enough to warrant shooting her with a Taser.

The woman's death rocked her family, the local community and the broader NSW community to its core, counsel assisting Sophie Callan SC said in opening the inquest.

The 95-year-old was described as an extremely generous woman who did charitable work and pursued a range of interests including golfing and travel until her late 80s.

O'Sullivan will examine systemic issues before the incident and will focus on dementia care and training for aged care staff, police and ambulance officers.

It was an opportune time to make recommendations that would save lives given Australia's ageing population, Callan said.

At the time of the incident, neither NSW Police nor NSW Ambulance officers were put through training that dealt with responding to incidents involving people with dementia.

A NSW Supreme Court jury found White guilty of manslaughter in November 2024.

He was sentenced to a two-year good behaviour bond in March 2025, a decision that was later upheld by the NSW Court of Criminal Appeal

The 36-year-old was removed from the force in December 2024.

NEVER MISS A STORY: Get your breaking news and exclusive stories first by following us across all platforms.

• Download the 9NEWS App here via Apple and Google Play
• Make 9News your preferred source on Google by ticking this box here
• Sign up to our breaking newsletter here

The lucky Lotto numbers have been revealed.

Diversions are in place on Te Puke Highway, motorists were warned to expect delays.

The man says he tried to help the interpreter with his immigration woes.

Matthew Ryan has owned more than 100 properties and is a prominent media commentator.