At least 54 protesters have been arrested in Hong Kong’s Mong Kok riot Monday night that left several people injured. Protests began after officers from the Food and Environmental Hygiene Department reached Shantung Street and Nelson Street in Mong Kok district to take action against unlicensed street vendors Monday night.

The arrests come as police officers investigate if violence during the protests was premeditated. The 47 men and seven women were arrested for several reasons, including alleged unlawful assembly, assaulting police, resisting arrest and possession of offensive weapons, the South China Morning Post reported.

“If there is enough evidence, we will consider charging the arrested persons [for] participating in riots,” Stephen Lo Wai-chung, the commissioner of police, said, according to the South China Morning Post, adding: “We strongly condemn the behavior of those people … [which] seriously damaged order in our society and public safety.”

Police officials reached the area Monday night in riot gear to clear out street vendors. The situation reportedly escalated after some more "radical localist” political groups, formed after the Umbrella Movement in 2014, announced that they will participate in the rally.

Police officials were seen armed with batons and hand-held water cannons, which they fired at protesters, the Guardian reported. Officials also fired gun shots in the air and used pepper spray at protesters as they set fire to garbage bins and other debris, broke car windows, and hurled stones at police. Several routes remained cordoned off by Hong Kong police Tuesday.

Hong Kong's leader, Chief Executive Leung Chun-ying, said, according to the Associated Press (AP), that authorities will prosecute members of the mob that attacked police officers. He also said that over 80 police officers and four reporters were injured during the violence.

“I believe the public can see for themselves from TV news reports the seriousness of the situation. The (Hong Kong) government strongly condemns such violent acts. The police will apprehend the mobs and bring them to justice,” Leung said, according to AP.

The hawkers are a common sight in Mong Kok around the Lunar New Year holiday. However, authorities in Hong Kong decided this year to take action against them. According to the AP report, the hawkers were supported by activists, who said that they were concerned that the local tradition of Hong Kong was being affected due to China’s efforts to tighten its hold over the semi-autonomous region.