Hundreds of thousands of people marched through Hong Kong in a bid to block a proposed extradition bill that would allow suspects to be sent to mainland China to face trial.

Police estimated the crowd at 240,000, but organisers said more than one million took part in what appeared to be the biggest demonstration since 2003 protests against a proposed national security law.

Sporadic violence broke out on Sunday but the march was mostly peaceful.

Protesters say the proposed law before Hong Kong’s semi-democratic Legislative Council would damage the city’s rule of law and put many at risk of extradition to China for politically motivated reasons.

Opposition to the planned bill has united a broad section of the community, from usually pro-establishment business people and lawyers to students, pro-democracy figures and religious groups.

Foreign governments have also expressed concern, warning of the effect on Hong Kong’s reputation as an international financial hub, and noting foreigners wanted in China risk getting ensnared in Hong Kong.