Philippine President Ferdinand Marcos Jr. held an emergency session with senior officials on Thursday against a backdrop of escalating political friction, coming just a day after shots were fired inside the Senate. There, Senator Ronald dela Rosa - a fugitive from the International Criminal Court - has barricaded himself, anxious about imminent capture.

The senator, once national police chief and key architect of former President Rodrigo Duterte's ruthless war on drugs, faces charges of crimes against humanity - identical to those leveled against Duterte.

Duterte stands poised to be the first ex-Asian leader to face trial at the ICC.

Late Wednesday, gunfire echoed through the Senate premises, prompting panic as people dove for cover. This unfolded hours after dela Rosa, popularly called Bato or Rock, urged followers via social media to rally, claiming authorities were en route to drag him from his legislative sanctuary.

The episode unleashed pandemonium and uncertainty, marked by a swarm of police and security personnel at the site, street demonstrations, and over a dozen rounds discharged mere minutes after Marines arrived to reinforce defenses.

Marcos huddled with security leaders Thursday, as police spokesman Randulf Tuano reported one suspect in custody. Probes continue, with authorities recovering spent shells, rifle clips, and related evidence.

The detainee supplied several names, though verification remains pending, Tuano shared on DZBB radio.

Questions linger over the shooters' identities and dela Rosa's whereabouts Thursday. His attorney, Jimmy Bondoc, entering the fortified structure, confirmed speaking with him overnight and presumed his presence.

As his counsel, Bondoc inquired about escape plans; dela Rosa replied in the negative, he told journalists.

Marcos' administration and agencies maintain no arrest directive targeted dela Rosa, offering no updates Thursday on those accused of storming the premises.

In a DZBB interview broadcast early Thursday - timing unclear - dela Rosa vowed to pursue every legal avenue against ICC extradition. Citing Duterte's detention conditions, he declared reluctance to contest the case in The Hague.

Dela Rosa Rejects Role in Duterte's Purported Mass Killings

Dela Rosa consistently refutes complicity in extrajudicial deaths.

Yes, circumstances shifted, he noted of Duterte. Visiting proves challenging. Co-incarceration offers no guarantee of shared cells or facilities.

Marcos pledged Wednesday night to unearth the truth behind the melee, as strains deepened over dela Rosa and the Monday impeachment of Duterte's daughter, Vice President Sara Duterte.

Currently in The Hague with her father, Sara - Marcos' erstwhile election partner - now battles existential political threats. An impending Senate impeachment trial threatens her 2028 presidential bid.

What unfolds is the regime deploying state machinery to crush dissenters who refuse alignment or backing, her office quoted her saying.

She denied recent contact with dela Rosa pre-shooting and warned of his prospective extraordinary rendition, mirroring what she deemed her father's unlawful seizure and ICC handover last year.

That perception held globally then, and mirrors current moves against Senator Bato dela Rosa, she asserted.

The ICC disclosed Monday an November-dated arrest warrant for dela Rosa. He petitioned the Supreme Court emergently to halt transfer, contending post-2018 Philippine withdrawal voids jurisdiction.

The tribunal holds authority over pre-withdrawal offenses.

Dela Rosa, Duterte's chief deputy, directed a brutal offensive slaying thousands of suspected traffickers. Human rights advocates decry orchestrated police executions and concealments.

Officers counter that over 6,000 fatalities in Project Double Barrel involved resisting, armed suspects.

Campaigners warn the true tally eludes reckoning, amid routine slum executions pinned by police on vigilantes and rivalries.