Photo/IllutrationPhilippine opposition Senator Antonio Trillanes IV holds copies of the decision of the trial court granting him amnesty during a news conference at the Philippine Senate on Sept. 5 in suburban Pasay city, south of Manila. (AP Photo)

MANILA--A Philippine senator who is President Rodrigo Duterte's fiercest critic in Congress remained holed up in the Senate on Wednesday to avoid what he considers an illegal arrest after Duterte voided his amnesty for his role as a rebel military officer.

Senator Antonio Trillanes IV told reporters after staying overnight in the Senate that his lawyers would file a petition to the Supreme Court to challenge the legality of Duterte's proclamation voiding his amnesty for taking part in failed coup attempts years ago.

Duterte also ordered the Department of Justice and the military to pursue criminal and administrative complaints against Trillanes, a former navy officer.

Trillanes told the police and military not to follow Duterte's "illegal order" for him to be arrested without a court warrant, saying his rebellion and coup cases were dismissed in 2011 without being questioned by the government after he availed of an amnesty offered by Duterte's predecessor.

Addressing military and police officers who may be pressured to enforce Duterte's order out of fear, Trillanes said "Duterte will not be there for long, please do not do anything illegal or unconstitutional."

Duterte's order, which was made public Tuesday while he was on a trip to Israel, has sparked a legal debate. Some legal experts have questioned whether Duterte can invalidate a rebel amnesty declared by a previous president and approved by legislators.

Justice Secretary Menardo Guevarra told a news conference Tuesday that Duterte voided Trillanes' amnesty because the senator had failed to comply with all of its requirements, including a clear admission of his involvement in past coup attempts.

Trillanes cannot invoke his congressional immunity from arrest because the crimes he allegedly committed, including rebellion, were serious and punishable by life imprisonment, Guevarra said.

During a televised Senate session, however, Trillanes showed video footage and news reports denying Duterte's basis for voiding his amnesty. The news reports showed an image of his amnesty application, which officials said they could not find, and carried remarks by Trillanes acknowledging his participation in the uprisings.

"That presidential declaration should alarm the justices of the Supreme Court because Duterte there exercises executive, legislative and judicial powers," Trillanes said. "If they affirm the presidential declaration, the president can issue warrants of arrest."

Despite questions on Duterte's move, military spokesman Col. Edgard Arevalo said Trillanes "will be reverted to his status as active military personnel subject to military law and military discipline." A military court may be reconstituted to try Trillanes after his amnesty was voided, Arevalo told reporters.

The 47-year-old former navy officer was detained for several years before his election to the Senate for involvement in three military uprisings from 2003 to 2007 to protest government corruption.

Duterte has openly expressed anger against Trillanes, who has accused him of large-scale corruption and involvement in illegal drugs. The volatile president has repeatedly denied the allegations.

Aside from Trillanes, another opposition senator, Leila de Lima, has been detained after being accused by Duterte of involvement in illegal drugs, a crime she has vehemently denied. A former human rights commission chief, de Lima investigated Duterte's alleged role in extrajudicial killings in a yearslong anti-drug crackdown when he served as mayor of southern Davao city for years.

Another Duterte critic, Maria Lourdes Sereno, was ousted by fellow justices from the Supreme Court in May after the government alleged that her appointment by Duterte's predecessor was legally flawed and petitioned for her removal.