Thousands of people have defied a police ban on Sunday and marched towards government headquarters after gathering in Causeway Bay.

The event has been billed as a “global anti-totalitarian march”, with similar protests planned around the world.

By 4pm the march had already descended into the familiar pattern, with radical protesters throwing petrol bombs outside the government compound, while others started fires outside Pacific Place. Police responded with tear gas and rubber bullets.

Police closed Wan Chai MTR station around 3.30pm after demonstrators vandalised fittings and sprayed graffiti.

Earlier, people had complained about heavy-handed police tactics, as officers stopped and searched people wearing black.

One woman said: “I think we have the freedom of assembly, and all they’re doing is merely walking on the street, wearing black and being young. I don’t think that’s any excuse to prosecute or search them.”

A volunteer first-aider at the march said he was stopped and searched by police. He said he suspected it’s because of the big bag he carries packed with medical supplies. He said he felt first-aiders were often targeted by officers.

“Sometimes maybe they can’t find the protesters, so the most significant target is first-aiders or even the press.

Many shops in Causeway Bay had shut ahead of the march.

Hysan, the Sogo Department store and the World Trade Centre were among the retailers announcing they would close.

The march – from Sogo to government headquarters – has not been approved by police.