Four protesters were arrested and 16 police officers were injured Thursday after a clash erupted between police and progressive groups outside the venue of the Luzon Economic Corridor (LEC) Investment Forum in Taguig City.

Col. Robert Baesa, deputy district director of the Southern Police District, said the four protesters were taken to the Taguig City Police Station and are expected to face charges over what authorities described as an illegal protest.

Baesa said 16 police officers were injured during the confrontation, with some allegedly punched by protesters.

The clash lasted for more than 30 minutes before the roughly 300 demonstrators dispersed from the area outside the Grand Hyatt Hotel in Bonifacio Global City, where President Ferdinand R. Marcos Jr. attended the investment forum.

The protest was organized by the Bagong Alyansang Makabayan (BAYAN), with demonstrators initially numbering around 200, according to a report by RH Jecelle Ricafort on DZRH’s Damdaming Bayan.

The protesters opposed the Pax Silica initiative, which they said was being pushed by the United States in the Philippines.

They also criticized the LEC investment forum, accusing the U.S. government of pursuing investments that could exploit the Philippines’ natural resources.

The confrontation occurred as authorities moved to disperse the protesters outside the hotel.