Protests in 2014. Photo: AP

Ahead of a visit from high-level Chinese officials later this week, Agence France-Presse reports, authorities in Hong Kong are gluing paving stones to the ground to prevent “localist” demonstrators critical of mainland rule from using them as missiles.

According to AFP, younger localists—advocates for more independence for Hong Kong, which has been semi-autonomous since 1997, when it was returned to China by Britain—have been radicalized in recent years, after the mostly peaceful protests of 2014 brought no change. In February, after police cracked down on street vendors selling fishballs (a local delicacy), demonstrators dug up bricks and threw them at police officers in a series of violent clashes.

The official purpose of Zhang Dejiang’s visit is to discuss President Xi Jinxing’s sprawling infrastructure project, known as “One Belt, One Road,” or the “New Silk Road,” the Washington Post reports. Zhang, the chair of the Communist-controlled mainland legislature, is the highest-ranking party official to visit Hong Kong in four years. He will also meet with pro-democracy politicians.

Zhang, who has previously warned Hong Kong not to “politicize everything” and focus instead on economic integration with the mainland, is unlikely to go off script. Still, the city’s pro-democracy camp no doubt hopes to broaden the agenda if they can, using his presence as a chance to raise concerns.

At least four representatives from pro-democracy parties will have the chance to meet with Zhang at a cocktail reception on May 18, according to a report in the South China Morning Post.

Some are not so optimistic: Cyd Ho, a Hong Kong legislator, told the Post she would not attend the meeting. “We hope to have a proper work meeting with Zhang Dejiang on the pressing issues facing Hong Kong,” she said. “We don’t want to just exchange pleasantries at a cocktail party.”

In addition to pouring glue between paving stones, police have also set up a no-protest security zone as part of “counter-terrorism measures.”

“Keeping protesters away is... ridiculous. It makes you feel like you are in North Korea,” Sham Tsz-kit of Civil Human Rights Front told AFP. “Zhang Dejiang is coming here to understand the situation in Hong Kong but now his eyesight will be completely blocked.”

Earlier this year, China released to Hong Kong two booksellers known to distribute literature critical of the state that it had detained. Three others are still missing. On Monday, China said that Hong Kong “will never leave the motherland again.”