Two of three men arrested over Hong Kong’s biggest bomb plot, discovered on eve of major anti-government protest, are members of pro-independence groups

At least two of the three men arrested at the weekend over the city’s biggest bomb plot are members of different pro-independence groups, suggesting there could have been collaboration across the movement, it emerged on Sunday.

Both groups have denied knowledge of the explosives found at an industrial building in Tsuen Wan, with one of them labelling the arrest as political suppression, saying their organisation never had any plans to use bombs.

A 27-year-old man, surnamed Lo, was arrested on Friday night at Lung Shing Factory Building in Texaco Road, following a police raid that led to the discovery of 10 petrol bombs and about 2kg of the powerful explosive triacetone triperoxide – the largest seizure of its type by the force since the return of the city from Britain to China in 1997.

While Lo was a member of Hong Kong National Front, one of the two 25-year-olds arrested on Saturday night, surnamed Tang, belonged to Hong Kong Independence Union.

Tang was arrested at his Fanling home while the third suspect, surnamed Hau, was arrested at his residence in Tsuen Wan.

Wayne Chan Ka-kui, convenor of the union, confirmed on Sunday that Tang was one of its members and was still being held by police to assist in investigations.

“We never had any plans to resort to explosives. I would say it is a political suppression,” Chan said.

The group also issued a post on social media, saying: “We would not be scared by even more arrests.”