Protesters in Hong Kong disrupted subway service during the morning commute on Tuesday by blocking the doors on trains, preventing them from leaving the stations.

Service was partially suspended on one line and delayed on another. Angry commuters argued with protesters in a stopped train and on the platform at Tiu Keng Leng station.

The disruption is part of a pro-democracy movement that has seen hundreds of thousands of people take to the streets this summer for marches and rallies. They’ve been protesting against a now-suspended extradition bill that would have allowed criminal suspects in Hong Kong to be sent to China to face trial in Communist Party-controlled courts.

The protests have shaken the government in Hong Kong and raised concern in Beijing.

The territory is part of China but has a fair degree of autonomy in local affairs.

Posts on Twitter showed long lines of commuters waiting for shuttle buses provided by the subway operator.