The court was sufficiently convinced that Krekar might try to flee, influence witnesses or tamper with evidence if released.
Krekar is charged in connection with the executions of Kurdish soldiers in a secret prison camp in northern Iraq, along with suicide bombings.
Krekar has denied the charges and claims he no longer is the leader of the suspected terrorist group Ansar al-Islam.
His defense attorney, Brynjar Meling, said he would appeal the custody ruling immediately. "It's as groundless as it always has been," Meling told news bureau NTB Monday morning.
