The U.S. is urging North Korea to immediately release detained Korean-American Kenneth Bae on humanitarian grounds.

State Department spokesman Patrick Ventrell said in a regular news briefing that the welfare of U.S. citizens is a critical and top priority for the U.S. government.

North Korea’s state-run Korean Central News Agency said on Saturday that a preliminary inquiry was completed and Pyongyang would put Bae on trial at its Supreme Court in the near future. Bae, who ran a travel agency in China, was arrested in November last year while accompanying five European tourists into North Korea’s Rason Special Economic Zone.

The North did not elaborate on the details of the charges against Bae.