Police in Hong Kong discovered a stash of a powerful homemade explosive as the semi-autonomous Chinese city readied for another major pro-democracy protest on Sunday following a pro-Beijing rally that attracted thousands.

Police said they found about 2 kilograms of TATP and arrested a man in a raid on a commercial building late Friday night.

TATP, or tri-acetone tri-peroxide, has been used in terrorist attacks worldwide.

Materials voicing opposition to an extradition bill that has sparked more than a month of demonstrations in Hong Kong were found at the site, local media said, but a police spokesman said no concrete link has been established and that the investigation is continuing.

In a rally that aimed to counter the pro-democracy movement, thousands of people filled a park in central Hong Kong on Saturday to support the police, who have been accused of using rough tactics on protesters. Some waved Chinese flags, and a giant screen behind the stage for speakers read “Safeguard Hong Kong.”

Many wore white, heeding a call by organizers, and the demonstrators did not wear masks or helmets, public broadcaster RTHK said. The anti-extradition law activists wear black and don protective gear against police pepper spray and batons.

Organizers said 316,000 people took part in the demonstration, while police put the turnout at 103,000.

Tags: ;