Ronald dela Rosa, police chief under ex-President Rodrigo Duterte, faces an ICC arrest warrant.

More than a dozen gunshots rang out at the Philippine Senate as police and marines moved in to arrest a senator wanted by the International Criminal Court for alleged crimes against humanity.

Al Jazeera’s Jamela Alindogan said journalists ran for cover as gunfire erupted on Wednesday evening minutes after soldiers with rifles and protective gear went up the stairs of the legislative building.

“About 15 shots were fired and we were forced to pull back,” Alindogan said, adding that security forces then ordered the evacuation of the building.

It was not immediately clear who fired the shots.

Philippine Senator Ronald dela Rosa had earlier said he was anticipating his arrest, urging people to come to the legislature to prevent him from being detained and sent to the ICC.

“I am appealing to you. I hope you can help me. Do not allow another Filipino to be brought to The Hague,” dela Rosa said in a video posted on Facebook on Wednesday.

Philippine law enforcement agents were earlier gathering outside the Senate building, Senate Sergeant-at-Arms Mao Aplasca said after dela Rosa’s message.

Former police chief dela Rosa, who was the top enforcer of ex-President Rodrigo Duterte’s so-called “war on drugs”, urged President Ferdinand Marcos Jr on Tuesday not to hand him over to the ICC, adding that he was ready to face justice at home.

Fearing arrest and hunkered down in his legislative office, dela Rosa said he had faithfully served his country.

The ICC unsealed an arrest warrant on Monday for dela Rosa, dated November, on suspicion of crimes against humanity, the same crimes 81-year-old Duterte is accused of as he awaits trial in The Hague following his arrest last year.

‘I worked faithfully’

Dela Rosa, better known as “Bato”, meaning “rock”, has been under the protective custody of the Senate since law enforcement agents entered the building on Monday, when he reappeared in public for the first time since November. He has denied involvement in illegal killings.

“I hope that, as the father of the nation, you will take care of all Filipinos. That is the role of government, to care for its people,” dela Rosa told reporters when asked what his message was to President Marcos.

“I did everything for the country. I did not enrich myself. I worked faithfully,” he said, his eyes welling with tears.

“Mr President, [you] may one day face a situation like this. You may also encounter problems, and then you will understand, you will feel what I am feeling right now.”

Dela Rosa was Duterte’s top lieutenant and oversaw a fierce crackdown during which police say more than 6,000 suspected drug dealers were killed in official operations.

Alindogan said “Duterte’s allies believe they are above accountability, they do not recognise the sovereignty of international law and refuse accusations against them”.

Al Jazeera’s correspondent added that while violent incidents are not unusual in Manila, it was unusual for confrontations to erupt in halls of justice “where there’s supposed to be some sort of civility”.

Thousands of drug users were also shot in slumland murders blamed on vigilantes or turf wars.

Police say those killed during operations had resisted arrest and reject allegations of systematic murders and cover-ups.

The “war on drugs” was the key platform that swept Duterte to power in 2016 as a tough-talking mayor who, during televised public speeches, promised to kill thousands of drug dealers while repeatedly daring the ICC to come after him.

Duterte’s defence team at the ICC has said he maintains his innocence and his tough rhetoric was designed to instil fear among criminals.