By Mikhail Flores and Nestor Corrales

MANILA, May 14 (Reuters) - Philippine authorities were seeking confirmation on Thursday of reports that a top politician wanted by the International Criminal Court had fled, a day after gunfire rang out at the Senate where he had taken refuge fearing his arrest.

Senator Ronald "Bato" dela Rosa, the former national police chief and top enforcer of ex-President Rodrigo Duterte's bloody "war on drugs", has been under Senate protection and is wanted for crimes against humanity, the same charges Duterte is accused of.

"Several sources confirmed that the Senator, Senator Bato, is no longer in the Senate premises. But we are still getting confirmation," Presidential Communications Undersecretary Claire Castro told a press conference.

Gunshots were heard late on Wednesday inside the Senate and people there scrambled for cover, hours after dela Rosa, 64, appealed on social media for supporters to mobilise, saying law enforcement agents were coming to arrest him.

The incident sparked chaos, with a heavy presence of police and armed guards at the Senate, protests outside and more than a dozen shots fired just moments after marines were called in to bolster security.

President Ferdinand Marcos Jr met security chiefs on Thursday and police said one person had been detained, with investigations underway to identify individuals who tried to enter the Senate, and bullet casings and assault rifle magazines recovered.

"The person has provided names, but these still need confirmation," police spokesperson Randulf Tuano told DZBB radio.

DELA ROSA WHEREABOUTS UNCLEAR

It was unclear who fired the shots, or if dela Rosa was still in the Senate on Thursday, with speculation rife that he had slipped away overnight.

The Hague-based court unsealed a warrant on Monday for his arrest, dated November, while he has filed an emergency appeal at the Supreme Court, arguing the ICC has no jurisdiction in the Philippines after its 2019 withdrawal from the international institution.

Earlier on Thursday, while entering the heavily guarded Senate, dela Rosa's lawyer Jimmy Bondoc said he spoke to him during the night and believed he was inside.

"I asked him if you have plans to leave, he said none," Bondoc told reporters.

The tough-talking dela Rosa enjoyed celebrity status as Duterte's top lieutenant, overseeing a fierce crackdown during which thousands of alleged drug dealers were slain, with rights groups accusing police of systematic murders and cover-ups.

Police reject that and say the more than 6,000 killed in Project Double Barrel were all armed and had resisted arrest.

Activists say the real death toll may never be known, with users and peddlers gunned down daily in mysterious slumland killings that police blamed on vigilantes and turf wars.

Marcos has sought to distance his government from the Senate drama and insisted no order was given to apprehend dela Rosa, who on Tuesday appealed to the president not to arrest him.

National Bureau of Investigation chief Melvin Matibag confirmed intelligence officers from the agency were at a building near the Senate on Wednesday, but were unarmed.

The possibility the incident could have been staged was also part of the investigation, he said.

In an interview with DZBB aired early Thursday, dela Rosa said he will "exhaust all available remedies" to block his ICC transfer and having learned about conditions Duterte was being held under, he was no longer willing to fight his case in The Hague.

It was unclear when the interview was conducted. Dela Rosa has denied involvement in illegal killings.

BIG POLITICAL TEST FOR MARCOS

The Senate standoff is a major challenge to the authority of Marcos, who relied on support of the influential Duterte family to win a 2022 election before an acrimonious fallout that led to him handing over predecessor Rodrigo Duterte to the ICC.

Duterte, 81, is set to become the first former Asian head of state to go on trial at the ICC. He denies inciting police to commit murder.

Political tension has mounted in recent days over dela Rosa and Monday's impeachment of the former president's daughter, Vice President Sara Duterte, Marcos' former ally and running mate.

Sara Duterte, who is in The Hague visiting her father, is fighting for her political survival, facing an impeachment trial in the Senate that could derail her run for the next presidency in 2028.

"What we are seeing now is the administration using all government resources to demolish political opposition," she said in comments shared by her office.

She said dela Rosa would be the subject of extraordinary rendition, likening it to what she called her father's illegal abduction.

"That is how the world saw it then. And that is also what they are trying to do now," she said.

(Reporting by Noel Celis, Nestor Corrales, Mikhail Flores and Karen Lema; Additional reporting by Lorenzo Lesaba; Writing by Martin Petty; Editing by Raju Gopalakrishnan)

Posted by: AAngeles/NET25 News