Would-be bomber fails to detonate in Indonesian church

People carry an unconscious friend to an ambulance in front of a church after a would-be suicide bomber failed to detonate explosives during Sunday service in Medan, North Sumatra, Indonesia, Sunday, Aug. 28, 2016. Police in the western Indonesian city said a would-be suicide bomber failed to detonate explosives in the packed church during Sunday mass. (AP Photo/Binsar Bakkara) (The Associated Press)

Indonesian police officers guard a church compound following an attack during Sunday Mass in Medan, North Sumatra, Indonesia, Sunday, Aug. 28, 2016. Police in the western Indonesian city said a would-be suicide bomber failed to detonate explosives in the packed church. (AP Photo/Binsar Bakkara) (The Associated Press)

Indonesian police officers guard a church compound following an attack during Sunday Mass in Medan, North Sumatra, Indonesia, Sunday, Aug. 28, 2016. Police in the western Indonesian city said a would-be suicide bomber failed to detonate explosives in the packed church. (AP Photo/Binsar Bakkara) (The Associated Press)

Police in western Indonesia say a would-be suicide bomber failed to detonate explosives in a packed church during Sunday Mass.

National police spokesman Maj. Gen. Boy Rafli Amar says the assailant left a bench and ran toward a priest at the altar but a bomb in his backpack apparently did not detonate and left the attacker injured.

Amar says the man kept running toward the priest with a burning backpack as the congregation chased and captured him.

The motive of the attack is not clear.

Indonesia, the world's most populous Muslim nation, has suffered a spate of deadly attacks by Muslim militants since the 2002 Bali bombings that killed 202 people.