Supporters of protesters who were arrested for obstruction of justice during a rally against the government's security legislation demanded Friday that they be released immediately and decried their "unjust arrest."

As of Friday afternoon, five protesters who took part in the Sept. 16 rally, organized as a last-ditch effort against the controversial security bills rammed through the Diet last Saturday, were still in custody at different police stations, their lawyer and supporters said.

A total of 13 participants were arrested that day, including university students. They were accused of obstructing police activities, such as by elbowing or head-butting officers, but some denied any wrongdoing, saying they never even touched the officers, said lawyer Yoshito Sakata, who has spoken to several of the detainees.