Subway workers blocked a group of disability rights activists from staging a subway protest during the morning rush hour on Tuesday, a day after authorities used force for the first time to deter their yearlong protest.

Since late last year, the Solidarity Against Disability Discrimination (SADD) has staged subway-riding protests at major stations in central Seoul on and off, demanding an increased government budget to protect the rights of people with disabilities, including mobility rights.

Wheelchair-bound activists have repeatedly boarded and disembarked trains to cause delays in metro services during the morning rush hour, drawing complaints from commuters.

In their latest protest on Tuesday, about 20 SADD members boarded a subway train on Line 4 at Sungshin Women's University Station at around 8 a.m. and got off at Dongdaemun History Culture Park Station.Immediately after disembarking, the activists tried to get back on the same train, but Seoul Metro workers blocked their entry, sparking protests from the activists.

"Let us get on the subway. Disabled people are citizens as well," they chanted.

The confrontation followed a 13-hour shoving match between activists and authorities at Samgakji Station on Line 4 on Monday.

Up to 640 riot police personnel were mobilized to block dozens of SADD activists from boarding a subway train from the morning through the night on Monday, the first time physical force was used to counter the subway protest in earnest.

Seoul Metro had 13 subway trains pass through Samgakji Station without stopping during the 13-hour confrontation, citing the railway safety act that prohibits rowdiness at train stations and facilities.