One of the most violent clashes yet between protesters and riot police in Hong Kong on Sunday night left two in critical condition and dozens in police custody after authorities trapped protesters attempting to go home in a shopping mall and attacked them with pepper spray.

Police told media outlets that they arrested at least 40 people and the local hospital in Sha Tin, a city within the Hong Kong autonomous region, took in 22 people. Among the 22, police said ten were police officers, one who lost a finger after a protester bit it off. Protest leaders identified at least two of their injured – Calvin Chu and William Liu – stating that police surrounded and beat them brutally as they were trying to take the Mass Transit Railway (MTR) home at the end of the protest. Two of the injured are believed to be in critical condition and four in serious condition; authorities did not specify if they were police officers or protesters.