MANILA, Philippines (AP) — A Philippine court ordered President Rodrigo Duterte’s fiercest critic in Congress arrested Tuesday after the president revoked the senator’s 2011 amnesty for a failed coup attempt and revived rebellion charges against him in an unprecedented legal move the legislator called a blow to democracy.

Sen. Antonio Trillanes IV walked out of the Senate, where he has sought refuge for weeks, and was taken by police to their headquarters in Makati city, where his fingerprints and mugshot were taken. After being booked by police, Trillanes said he would go to a nearby court to post bail.

“Definitely our fight will continue,” Trillanes told DZMM radio at the police headquarters, where he was accompanied by his lawyers and a few allied senators.

“We will not be cowed by these obstacles in fighting for the truth, justice and democracy,” he said.

Duterte has been highly sensitive to criticism, especially over his anti-drug crackdown that has left thousands of mostly poor suspects dead since he took office in mid-2016. Trillanes has also accused the president of large-scale corruption and involvement in illegal drugs, which Duterte has denied.

Duterte said he voided Trillanes’ amnesty last month because the senator had failed to file a formal amnesty request and acknowledge guilt for involvement in at least three failed coup attempts several years ago. Trillanes has strongly denied the president’s claims and has provided news reports and defense department documents to counter Duterte’s claims.

The Department of Justice has asked two courts to issue warrants for Trillanes’s arrest and resume criminal proceedings against him. One of the courts issued the arrest warrant against the senator on Tuesday.

Aside from the rebellion and coup-related charges in the two courts, Duterte has also ordered the military to resume an inquiry into the senator’s role in the mutinies.

Legal experts and the Integrated Bar of the Philippines, the largest lawyers’ group in the country, have expressed alarm over the legal moves against Trillanes for offenses that were canceled by a 2011 amnesty approved by Duterte’s predecessor and Congress.

The lawyers’ group said the move against Trillanes “runs roughshod over the constitutional guarantee against double jeopardy,” or holding a person to answer twice for the same offense.

Duterte has also accused Trillanes, without offering evidence, of plotting with other opposition politicians, including the Liberal Party and leftist groups, to oust him. Trillanes and opposition groups have dismissed the claim as a lie and asked him to focus instead on addressing poverty, inflation, rice shortages, traffic jams and a decline in the value of the peso currency.