Hundreds of Hong Kong medical workers and other anti-government protesters rallied in the Chinese-ruled city’s financial center on Saturday, angry at perceived police brutality during more than four months of sometimes violent unrest.

Pro-democracy activists have attacked police with petrol bombs and rocks and shone lasers in their eyes. One officer was slashed in the neck with a knife.

Police have responded with tear gas, water cannons, rubber bullets and occasional live rounds, wounding several protesters, many of whom received treatment from volunteer first responders at the roadside.

A 26-year-old nurse, who gave his name only as Stephen, said police would often come into the hospital where he works on the Kowloon peninsula and stand outside the wards or search for protesters in the accident and emergency department.

“Sometimes they bring their guns and weapons. The patients may be scared. This is not good practice,” he said. “The protesters have injuries. This searching must be done after they are healed.”

He said he worked as a first responder at protest sites in his spare time.

“I didn’t tell any of my supervisors — only some colleagues with the same values,” he said. “But when I see people injured, I have to provide first aid.”

Police deny accusations of brutality, saying they have shown utmost restraint in life-threatening situations and issue warnings to protesters with color-coded signs before they respond with tear gas or baton charges.

Protesters are angry about what they see as creeping Chinese interference in Hong Kong, a former British colony that returned to Chinese rule in 1997 under a “one country, two systems” formula intended to guarantee freedoms that are not enjoyed on the mainland.

China denies meddling. It has accused foreign governments, including the United States and Britain, of inciting the unrest.

The demonstrators gathered peacefully for Saturday’s “resisting tyranny” protest, occasionally chanting “Hong Kong people, resist.”

This weekend demonstrations are planned in the city’s financial district on Hong Kong Island and another on Sunday on the Kowloon side of the harbor.

Pro-democracy activists were preparing to demonstrate for the 21st straight weekend as unrest spreads around the globe, from South America to Europe to the Middle East.

Protesters in Hong Kong will look to keep up momentum in the monthslong fight with officials in Beijing for greater democracy. Earlier this week, reports surfaced this week that China’s leaders were mulling a plan to replace Hong Kong Chief Executive Carrie Lam by early next year in a bid to calm public anger.

All efforts so far by Hong Kong’s authorities to quell the protests have largely failed, from banning marches and withdrawing the proposed extradition bill to using an emergency law to outlaw face masks and pledging to make housing more affordable.

The protests have been cited as inspiration for demonstrators around the world who have flooded the streets of major cities this month over economic inequality, regional grievances and alleged corruption.

Spanish authorities are facing down separatist riots in Catalonia. In Chile, opposition to a 4-cent subway-fare hike has snowballed into the worst unrest in decades, with at least 18 people killed so far. And in Lebanon, more than a week of nationwide protests, including hundreds of thousands demonstrating in Beirut, have pressured the country’s leader to shake up his Cabinet. There have also been protests in Iraq.

Data due in Hong Kong next week will likely signal a technical recession after a contraction in the second quarter. The benchmark Hang Seng Index tumbled 8.6 percent last quarter, the biggest loss among major global gauges tracked by Bloomberg.