There is a strong smell of tear gas near Queen Elizabeth Hospital in Jordan, South China Morning Post reports.
It says medical staff are distributing and putting on face masks to protect themselves against hazardous substances.
“We have asked colleagues and patients to close the windows,” a nurse is quoted as saying. “Seems the hospital is installing some air ventilation machines around the place. I hope it’s not too late.”
Some patients leaving the hospital are covering their mouths and noses, the SCMP adds.
* Police and protesters – at Hong Kong Polytechnic University and in other areas – are engaged in a game of cat and mouse.
* Intense clashes erupted overnight as police surrounded the campus with hundreds of protesters inside
Police tried to re-take the campus at 05:30 local time (21:30 GMT) but eventually retreated as fires raged at entrances.
* Daylight saw yet more tear gas fired as protesters attempted to leave. Others protested to try to divert police attention.
* Months of anti-government protests – sparked by a proposal to allow suspects to be extradited to China – have caused turmoil
* But the intensity of the past week has seen a sharp escalation of protest and the universities are now a battleground.