Indonesian President Joko Widodo strongly condemned a suicide bomb attack that injured some 20 people on Sunday in the country, calling the attack an "act of terrorism" and urging people to remain calm.

In a video broadcast, the president said the government would ensure that everybody can worship freely "without fear."

The suicide bombing occurred at around 10:30 a.m. local time outside a church hosting around 100 people in Makassar, the capital of South Sulawesi province in eastern Indonesia. 

Police said two people tried to enter the church grounds on a motorbike, and a church security guard was trying to prevent the motorbike from entering the compound when the blast occurred.

The two bombers, one male and one female, were killed, spokesman of the Provincial Police Office, Senior Commissioner E. Zulpan told local media.

A witness at the scene described the explosion as "very strong." News footage of the aftermath showed damaged cars near the building and police tape cordoning off the area.

The incident occurred when Christians in Indonesia were celebrating Palm Sunday, a Christian feast that falls on the Sunday before Easter.

Extremists in Indonesia have been targeting churches. In 2018, dozens of people were killed when suicide bombers detonated bombs at three churches during Sunday services in the city of Surabaya in East Java. 

(With input from Xinhua, AFP)