Police in Hong Kong have arrested 200 people and said the arrested were aged between 12 and 65 and their offences included unlawful assembly, assaulting a police officer and failing to produce proof of identity.

A 22-year-old man was found to have materials believed to be intended for making petrol bombs, police said.

Police fired pepper spray at journalists and activists, and conducted stop and search operations on members of the public and media.

The Hong Kong Journalists’ Association said some members of the press were prevented from filming.

“Some journalists who were sprayed by pepper spray were not allowed to receive immediate treatment, and they were requested to stop filming,” said Chris Yeung.

The financial hub is gearing up for protests over the next few months, with activists calling for two million people to gather for an annual march on July 1 that marks the anniversary of its handover from British to Chinese rule in 1997.