Jakarta – Two men opened fire at a church during an Easter service in an eastern Indonesian town and lightly wounded seven people, including a four-year-old girl, police said on Sunday.

The shooting occurred on Saturday when Christians gathered at the church in the town of Poso, for years a scene of fighting between Muslims and Christians in the world's largest Islamic nation by population.

"Two men dressed in black masks stormed into the church and opened fire," Poso deputy police chief Rudy Tranggono told Reuters. "Seven people, including a four-year-old girl, suffered light injuries," he said.

"We have yet to detain any suspects and determine the motive of the shooting," Tranggono added.

Despite the attack thousands of Christians in Poso, some 1,600 km northeast of Jakarta, flocked to churches in the lakeside town for Easter Sunday masses, Tranggono said, adding hundreds of police had been deployed to secure the services.

At least 2,000 people have been killed in fighting between Muslims and Christians in Poso since 1999.

There had been a period of calm in Poso after a peace deal reached in late 2001, but small and sporadic bursts of violence do occur.

Almost 90 percent of Indonesia's 220 million people are Muslim but Poso has an equal number of Muslims and Christians.