MANILA, Philippines — 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 in failed coup plots as a former rebel military officer.

Sen. 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. Amid the standoff, a small group of soldiers and policemen, including SWAT commandos, was seen outside the Senate.

Duterte also ordered the Department of Justice and the military to pursue criminal and administrative complaints against Trillanes.

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 after he accepted 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."

Trillanes, a 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'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.

Despite questions on Duterte's move, the Defense Department said it had deployed officers to the Senate to take custody of Trillanes, who would be made to face a military court inquiry over alleged misconduct for his role in past uprisings.

"With our MPs (military police) and legal officer in the Senate, we are awaiting to acquire his custody for the purpose of returning him to military control and for him to face a court martial," Defense Department spokesman Arsenio Andolong told reporters.

The Department of Justice, meanwhile, asked a court to issue an arrest warrant for Trillanes and restrain him from leaving the country. The court did not immediately issue a warrant and gave Trillanes five days to respond to the government move and set a hearing for next week.

Justice Secretary Menardo Guevarra said Duterte voided the amnesty because Trillanes 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.

"I have no case, but they want to arrest me," Trillanes said. "The police and military are here. There is no basis, so that is now our situation."

"We used to have democracy, there was due process. Now, there is none," he said.

Known for his temper and expletives-laden outbursts against critics, the 73-year-old Duterte has openly expressed anger against Trillanes, who has accused him of large-scale corruption and involvement in illegal drugs. The volatile leader 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 solicitor-general alleged that her appointment by Duterte's predecessor was legally flawed and petitioned for her removal.