Hong Kong police say nearly 1,000 people have left the campus of the Hong Kong Polytechnic University (PolyU) following clashes between rioters and the police force since last week.

One third of the students are aged 18 and under, Chief Superintendent Ho Yun-sing, district commander of Yau Tsim District told reporters at the latest briefing on Wednesday afternoon.

Police have made special arrangement to take the personal information of underage students who peacefully left the campus, Ho said, adding that they reserve the right to pursue them afterwards.

Ho appealed to those still inside the campus to cooperate with the police and not to escape in dangerous ways, including abseiling from bridges.

"We wish for a peaceful solution to the situation," Ho reiterated. "All must give up their weapons and leave the campus in a peaceful and orderly manner."

Rioters have been occupying the PolyU campus for over a week, during which police have repeatedly warned them to leave.

A total of 3,900 petrol bombs were found at the Chinese University of Hong Kong (CUHK), and the number of petrol bombs found at PolyU is estimated to be larger, police told reporters.

(Cover: A general view from the campus of the Hong Kong Polytechnic University (PolyU), Hong Kong, China, November 19, 2019. /Reuters Photo)