Muslim-majority Indonesia has seen a surge in religious tensions during recent years, with hardline Muslims calling for a nationwide implementation of Sharia law.

A knife-wielding man has attacked church-goers at a Catholic church service in the Indonesian city of Yogyakarta, injuring 4 people, before being shot by the police, a Yogyakarta police spokesman said.

"We cannot confirm yet if this was a terror-related incident," Yogyakarta said, adding that "we can confirm the suspect has been detained and is being treated at the hospital."

According to the spokesman, the attacker had been shot in the stomach, while the condition of the wounded victims is still unknown. The police are currently investigating the motives of the assailant, who is believed to be a university student.

Indonesia, the country with the largest Muslim population in the world, is also home to other religious minorities, including Christians and Hindus.

Religious tensions have risen in recent years due to hardline Muslims, calling for a nationwide implementation of Sharia as well as to the surge of homegrown radicalism, inspired by Daesh.