Activist Adriatik Lapaj was injured during a violent confrontation with police late Sunday night outside the prime minister’s office, authorities said. Four people were arrested, nine others are under investigation, and five individuals were sent to the Trauma Hospital, including Lapaj and two police officers.

Lapaj was struck in the head by a gas canister but has since been discharged. Officials said he is in stable condition with no serious injuries. One police officer suffered a broken leg.

Police intervened to remove a plastic tent erected on the sidewalk of Deshmoret e Kombit Boulevard, where protesters have been camping since Dec. 8. The protesters, including Lapaj and members of the “Shqipëria Bëhet” movement, aim to force the resignation of the current government.

Lapaj, who is also under police investigation, posted from the hospital that he would continue his protest despite the legal actions against him.

Those arrested were identified as Edison Haklaj, Alfred Matoshi, Eligert Hima and Ergjys Llanaj, who police said threw hard objects at officers. This marked the second confrontation in one day over the protest tents.