Running battles between police and protesters on Monday featured raging fires, tear gas and flaming vehicles. Some demonstrators managed to escape Hong Kong Polytechnic University in Kowloon by climbing over walls, while police arrested dozens of others — sometimes tackling them to the ground or pounding them with batons.

On Monday evening, the government warned those inside to surrender peacefully and urged others to stay away from the site as protesters pleaded for reinforcements to battle police. Medical personnel were allowed in to tend to the wounded, while university officials called for a negotiation and parents held signs saying “Save the Kids.”

“Police have repeatedly made appeals and people in PolyU campus should listen,” Chief Executive Carrie Lam said in a Facebook post. She’s scheduled to hold a weekly press briefing Tuesday morning.