THOUSANDS of Hong Kong football fans booed loudly and turned their backs when the Chinese national anthem was played before a World Cup qualifier match against Iran on Tuesday, taking the city’s months of often violent protests into the sports realm.

The crowd broke out into “Glory to Hong Kong,” a separatist song urging a struggle against the rest of China, which regained sovereignty over the city in 1997 after it had been occupied by Britain for 155 years.

After the match started, fans chanted “fight for freedom” and “revolution of our times.” One person carried a blue poster that read “Hong Kong is not China.”

Hong Kong has been roiled by protests since June over an extradition Bill that would have allowed people suspected of some serious crimes to be sent for trial in other jurisdictions, including the Chinese mainland. The government promised last week to withdraw the Bill but that failed to placate the protesters, who have torched metro stations and smashed property over the last week.

Security at the Hong Kong Stadium was tight, with fans frisked to ensure they did not bring in anything that could be used as a weapon. Iran, Asia’s top team, had sought to move the match, citing safety concerns over the unrest, but the request was rejected by Fifa.

Stadium announcers said 14,000 spectators attended the game.

Iran beat Hong Kong 2-0.

“Hong Kong people are united. We will speak up for freedom and democracy,” one of the spectators, Leo Fan, said as members of the crowd continued to chant slogans and sing protest songs as they left. However, hundreds of thousands of residents have also joined pro-China demonstrations that have condemned the violence.

In July, Hong Kong fans chanted slogans and waved banners when Premier League champions Manchester City played local team Kitchee at the stadium.

Clashes have become increasingly violent, with police firing tear gas after protesters vandalised railways, lit street fires and blocked traffic over the weekend.