QUETTA, Pakistan (AP) – A powerful bomb exploded Saturday at a gathering of minority Shiite Muslims in a remote town in southwestern Pakistan, killing at least 15 people and wounding 25 others, police said.

Thousands of worshippers had congregated at the shrine of a Shiite saint near the town of Naseerabad, about 210 miles south of Quetta, when the bomb went off outside, said Merab Khan, a local police official.

It was not immediately known who was behind the blast. Police said they were investigating.

“Right now people are angry. They are wailing and crying. Some of them have blocked roads in the town and we are trying to control the situation,” Khan told The Associated Press.

Khan said the bodies and injured, some in critical condition, were transported to a nearby hospital. He expected the death toll to rise.

Pakistan has a history of sectarian violence, mostly blamed on rival majority Sunni and minority Shiite extremist groups. About 80 percent of Pakistan’s 150 million people are Sunnis and 17 percent Shiites.