Tens of thousands of Hong Kong demonstrators surrounded the Chinese-ruled city’s legislature on Wednesday, forcing it to postpone a second round of debate on an extradition bill that would allow people to be sent to mainland China for trial.

Axar.az reports citing Reuters that, the protesters, most of them young people dressed in black, erected barricades as they prepared to hunker down for an extended occupation of the area, in scenes reminiscent of pro-democracy “Occupy” protests that gridlocked the former British colony in 2014.

Protesters rallied in and around Lung Wo Road, a main east-west artery near the offices of embattled Hong Kong Chief Executive Carrie Lam, as hundreds of riot police, some armed with batons and plastic shields, warned them to stop advancing.

“Didn’t we say at the end of the Umbrella movement we would be back?” pro-democracy lawmaker Claudia Mo said, referring to the name often used for the “Occupy” demonstrations.

“Now we are back!” she said as supporters echoed her words.

Others once again called for Lam to step down.

Opposition to the bill on Sunday triggered Hong Kong’s biggest political demonstration since its handover from British to Chinese rule in 1997 under a “once country, two systems” deal guaranteeing it special autonomy, including freedom of assembly, free press and independent judiciary.

But many accuse China of extensive meddling since then, including obstruction of democratic reforms, interference with local elections and of being behind the disappearance of five Hong Kong-based booksellers, starting in 2015, who specialized in works critical of Chinese leaders.

Lam has vowed to press ahead with the legislation despite deep concerns in the Asian financial hub, including among business leaders, that it could undermine those freedoms and investor confidence and erode the city’s competitive advantages.

The government said debate on the bill that was due to take place in the city’s 70-seat Legislative Council on Wednesday would be delayed until further notice.

The legislature is controlled by a pro-Beijing majority.

“We won’t leave till they scrap the law,” said one young man wearing a black mask and gloves.

“Carrie Lam has underestimated us. We won’t let her get away with this,” he said.

Beijing again reiterated that the “one country, two systems” formula is best for maintaining long-term prosperity and stability.

“The practice of ‘one country, two systems’ in Hong Kong has achieved remarkable success. This is an undeniable objective fact,” Taiwan Affairs Office spokesman An Fengshan told a regular news briefing in Beijing.