Police are seen outside Saint Joseph's Catholic Church after a suspected terror attack by a knife-wielding assailant on a priest during Sunday service in Medan, North Sumatra, Indonesia August 28, 2016 in this photo taken by Antara Foto. Picture taken August 28, 2016.Antara Foto/Irsan Mulyadi/ via REUTERS

Police are seen outside Saint Joseph’s Catholic Church after a suspected terror attack by a knife-wielding assailant on a priest during Sunday service in Medan, North Sumatra, Indonesia August 28, 2016 in this photo taken by Antara Foto. Picture taken August 28, 2016.Antara Foto/Irsan Mulyadi/ via REUTERS

Police are seen outside Saint Joseph's Catholic Church after a suspected terror attack by a knife-wielding assailant on a priest during Sunday service in Medan, North Sumatra, Indonesia August 28, 2016 in this photo taken by Antara Foto. Picture taken August 28, 2016.Antara Foto/Irsan Mulyadi/ via REUTERS

August 31, 2016 12:15 PM (UTC+8)