Mass protests in Chinese-ruled city that began in June show little sign of abating, piling pressure on administration.

Hong Kong police fired beanbag rounds and used pepper spray in late-night skirmishes with pro-democracy protesters on Tuesday night that left two men in hospital, local broadcaster RTHK said.

The clashes took place outside the Mong Kok police station and in Prince Edward metro station, with one man taken out on a stretcher with an oxygen mask over his face, television footage showed.

Videos showing the man being apprehended by the police in the station have been widely shared on social media with protest groups and activists saying it is evidence of the police brutality they say is widespread and needs to be investigated.

The police, who have repeatedly denied using excessive force, did not immediately respond to a request for comment. Hong Kong police are due to hold a news conference at 4 p.m. (0800 GMT).

Three men, aged between 21 and 42, were taken to Kwong Wa Hospital late on Tuesday, a hospital authority spokeswoman said.

Two, including the man stretchered out of Prince Edward station, were in a stable condition and one had been discharged, she said.

Hundreds of thousands of people have taken to the streets since mid-June in sometimes violent protests calling for greater democracy in the former British colony, which reverted to Chinese rule in 1997, posing a direct challenge to the central government in Beijing.

Pressure on leader

The continued unrest is piling pressure on Hong Kong’s leader Carrie Lam, who told a group of businesspeople last week that she had “very, very limited” ability to end the crisis and it had been elevated “to a national level”, a reference to the leadership in Beijing.

Lam on Tuesday said she had never discussed resignation with Beijing and believed her government could solve the crisis without Beijing’s help.

China denies it is meddling in Hong Kong’s affairs but warned again on Tuesday that it would not sit idly by if the unrest threatened the country’s security and sovereignty.

With German Chancellor Angela Merkel due to visit Beijing in a the coming days, prominent Hong Kong activists are urging her to remember life under East Germany’s dictatorial regime in dealing with the Chinese government.

Activists’ appeal

In an open letter to Merkel published in Wednesday’s Bild newspaper, activists including Joshua Wong, head of the Demosisto pro-democracy movement, said Germany should be on its guard.

“Chancellor Merkel, you grew up in East Germany,” Wong wrote.

“You experienced at first hand the horrors of a dictatorial regime. We would like you to show the courage and determination against authoritarian and unjust regimes that inspired Germany and Europe before the end of the Cold War.”

The letter was also signed by Joephy Wong and Alice Yu, artists from Hong Kong now living in Germany where the protesters’ cause is popular.

The demonstrations began over a now-suspended extradition bill, but have evolved into a push for greater democracy, including the territory’s right to elect its own leaders. Beijing has said giving Hong Kong universal suffrage is out of the question.