A court in Thailand has extended the detention of 15 pro-democracy activists arrested earlier this week for protesting against military rule.

A lawyer for the activists said Thursday that the court agreed to a police request for a further 12 days detention.

They were arrested Tuesday at a protest marking the fourth anniversary of a 2014 military coup and calling for elections this year.

Police have charged each activist with several offenses including violating a ban on political assembly and obstructing officials.

Documents that police submitted to the court said they needed more time to complete their investigations. They also argued that bail should be denied because of the seriousness of the alleged offenses.