Kuala Terengganu police chief Azli Noor said the 33 fans, brought in at 10.15am today, were among some 400 supporters detained yesterday to undergo urine tests, following the incident at around 6.30pm.

“We have arrested them for further investigation into the incident,” Harian Metro reported him as saying.

Several videos of Selangor FC supporters, marching from the city centre to Seberang Takir holding up club flags and lighting flares, had gone viral since yesterday.

The incident occurred ahead of a match at Sultan Mizan Zainal Abidin Stadium yesterday, which saw Selangor FC hold Terengganu FC to a 1-1 draw.

Terengganu police chief Khairi Khairudin later said 21 of the 33 remanded tested positive for THC use, including seven university students and a secondary school student.

Sinar Harian reported him as saying police had received a report from an assistant operator at the drawbridge yesterday alleging that the fans were blocking traffic and lighting flares, endangering commuters.

Khairudin said police then dispatched 10 buses to the scene to detain 412 people, bringing them to the state police headquarters for further investigation.

“Police seized 19.1g of a drug suspected to be marijuana and 0.37g of Erimin 5, believed to be for personal use, from three detainees,” he said.

Khairi said the 21 who tested positive for THC use are being investigated for drug use under Section 3(1) of the Drug Dependants (Treatments and Rehabilitation) Act 1983.

Nine people are being investigated for possession of flares under Section 8 of the Explosives Act 1957 and Section 186 of the Penal Code for obstructing a public servant. Khairi said police also seized 70 flares, 54 of which had already been set off.