MAKASSAR, Indonesia—Two attackers blew themselves up outside a packed Roman Catholic cathedral during a Palm Sunday Mass on Indonesia’s Sulawesi island, wounding at least 20 people, police said. A video obtained by The Associated Press showed body parts scattered near a burning motorbike at the gates of the Sacred Heart of Jesus Cathedral in Makassar, the capital of South Sulawesi province. Rev. Wilhelmus Tulak, a priest at the church, said he had just finished celebrating Palm Sunday Mass when a loud bang shocked his congregation. He said the blast went off at about 10:30 a.m. as a first batch of churchgoers was walking out of the church and another group was coming in. He said security guards at the church were suspicious of two men on a motorcycle who wanted to enter the building and when they went to confront them, one of the men detonated his explosives. Police later …