A man armed with a sword has attacked a church congregation in Indonesia, injuring at least four people before being shot by police.

The assault took place during the Sunday mass in Sleman district in the southern Indonesian province of Yogyakarta.

Video footage showed people in the church hurling books at the sword-wielding man as he lunged toward them.

Among the four injured in the attack was a police officer who, as witnesses said, tried to subdue the assailant with the help of a priest.

“After the warning shot was fired, the attacked charged toward the officer with his sword. The officer then shot him below his stomach, but he managed to injure the cop before being subdued,” said Andhi Cahyo, a congregation member.

All victims were taken to hospital for treatment.

The motive behind the Sunday attack was not immediately clear; however, churches are regarded as a common target for extremist groups.

Last year, the military chief in Jakarta announced that Daesh was present in almost all Indonesian provinces as the group lost territory in the Middle East.

Indonesian law enforcement agencies have arrested hundreds of militants during a sustained crackdown in recent years.

At least 400 Indonesians are believed to have previously joined the Daesh terrorist group in Iraq and Syria, where the Takfiri outfit used to control territory.

Indonesia and neighboring Malaysia and the Philippines have geared up to confront the potential threats posed by Daesh militants returning to their home countries.