HONG KONG (AP) — Hong Kong police on Tuesday arrested eight pro-democracy activists over their role in an unauthorized protest last summer, widening a crackdown on dissent in the semi-autonomous Chinese city.

The arrests, which included several former lawmakers, are tied to a July 1 demonstration in which thousands defied a protest ban and rallied on the streets against a national security law imposed on the city by Beijing the day before.

Former pro-democracy lawmakers Wu Chi-wai, Eddie Chu and Leung Kwok Hung were arrested at their homes on charges related to organizing and participating in the protest, according to Facebook posts on their respective pages.

Hong Kong police said in a statement that eight men aged between 24 and 64 had been arrested for inciting, organizing and taking part in an unauthorized assembly.

Traditionally, a protest march is held every year on July 1 — the day Hong Kong was handed from British to Chinese control in 1997 — but this year’s protest was banned with authorities citing the health risks from the pandemic.

Hong Kong and Beijing have increasingly clamped down on dissent in the city since the introduction of the national security law, which was aimed at curbing months of political unrest and protests against the government.

The crackdown has led to accusations that Beijing is violating the autonomy it promised Hong Kong would have following the 1997 handover. It also has triggered warnings the ruling Communist Party is damaging Hong Kong’s appeal as a global business center and one of Asia’s most dynamic cities.

More than 370 people were arrested on July 1, with at least 10 arrested under the national security law.

In August, the U.S. imposed sanctions on 11 officials from mainland China and Hong Kong, including Hong Kong leader Carrie Lam, for undermining the city’s autonomy. The U.S. sanctioned another 14 Chinese officials on Tuesday for undermining the city’s democratic processes.