Hundreds of anti-government protesters gathered on Monday in defiance of a threat by police to make more arrests, a day after nearly 100 demonstrators were detained for breaching public health measures against the coronavirus.

Demonstrators demanded the release of jailed activists, raising prospects for another confrontation between police and protesters, who are calling for an end to military dominance of politics and reform of the powerful monarchy.

“Free our friends,” they shouted.

Police had earlier on Monday warned they would arrest more people participating in anti-government protests.

“We have prepared troops to maintain order,” Piya Tavichai, deputy head of the Bangkok police, told reporters.

Piya said 99 people were arrested on Sunday in front of Government House, saying the arrests were necessary under a law forbidding large public gatherings to prevent coronavirus spread.

Thai Lawyers of Human Rights, which is representing those detained on Sunday, said a court had agreed they could be released on bail.

The mostly student-led movement has taken aim at the military for entrenching its role in civilian politics, especially since Prime Minister Prayuth Chan-ocha seized power in a 2014 coup when he was army chief.

The activists say elections held in 2019 were under rules designed to cement Prayuth’s hold on power. Prayuth and his coalition government allies say the vote was free and fair.

Prayuth on Monday told reporters the weekend arrests were justified.

“You have to look at the law. If I don’t take action, there will be disruption in traffic. We are just taking back space. There have been many warnings,” said Prayuth.

Dozens of people have been detained at protests in recent months under disease control and public order laws, but Sunday’s protest represented one of the largest number of arrests at a single rally.

Additionally, at least nine leaders of the movement are jailed pending trial under a law against insulting the Thai monarchy, which carries a maximum 15-year penalty.