About 20 suspected triad members set upon a group of schoolboys from a rival gang at a Hong Kong public housing estate on Thursday night, a police source said, as the force hunted for the perpetrators. The police insider said a dispute between the two triad gangs – Sun Yee On and Wo Shing Wo – in Tsim Sha Tsui several days ago sparked the attack, which happened outside On Tai Estate in Sau Mau Ping shortly before 11pm. An online video of the latter attack shows a group of five or six teenage boys running onto On Sau Road while being chased by a gang of 20 men carrying weapons including wooden planks. The footage shows one of the targets trip over and hit the ground, before being caught and beaten up by the attackers, who fled before police were called in. Student, 20, arrested over home-made bombs found at school campus Officers combed the area, but made no arrests. Police found five injured men aged between 16 and 18 at the scene. Four of the injured were taken to United Christian Hospital in Kwun Tong and the fifth was treated at Queen Elizabeth Hospital in Yau Ma Tei. The five, who were all secondary school students, were not seriously injured, according to the source. He said he believed the students were associated with the Wo Shing Wo triad gang and the attackers were from the Sun Yee On triad. Detectives from the Sau Mau Ping criminal investigation unit were handling the case. Police handled 3,902 reports of serious assault across the city in 2019, an 8.8 per cent rise from 3,585 in the year before.