Hong Kong Polytechnic University on Wednesday. Photo: Yang Sheng/GT

Hong Kong's new police chief said on Friday that the police haven't set any deadline for the peaceful resolution of the Hong Kong Polytechnic University incident, and urged those still inside the campus, including rioters, protesters and others, to come out and surrender as soon as possible.

Hong Kong Police Force Commissioner Chris Tang Ping-keung said during a press conference at the Police Sports and Recreation Club that the environment inside is deteriorating, so he urged the people inside to consider that their family worried about them, and come out of the university.

"There are many explosives, including Molotov cocktails, inside the university. The conditions are deteriorating. To the people who still remain inside, I think you do not want your family members, friends and visitors to be worried.

"I hope you can come out as soon as possible and peacefully resolve the matter."

Hours earlier, the protesters were offered a way out by self-proclaimed medical assistants, who entered the grounds at about 12:30 am after police reportedly handed them a numbered card, the South China Morning Post reported.

A group claiming to be first-aiders entered the site early Friday morning, telling those inside they could lead them out without facing immediate arrest. Dozens of radicals were still believed to be holed up in the Hung Hom campus of the university on Friday as the stand-off with police entered its sixth day.

Tang also reaffirmed the promise that the police will not arrest minors on the spot or those with immediate medical needs. But those over 18 would immediately be arrested, he noted. He stressed that the police force reserves the right to arrest underage protesters later.