A bomb ripped through a Shiite procession killing 16 marchers and wounding over 20 others in central Pakistan on Sunday, police said, as the spectre of sectarian violence again loomed.
No group claimed immediate responsibility for the carnage in Punjab province.
Dunya TV news broadcast footage of several dead and bloodied bodies lying on the ground. Pictures showed a cloud of grey smoke rising in the sky with people beating their chests and heads and crying for help.
"The evidences showed that it was a bomb blast, we are examining whether it was a planted one or a timed device," Suhail Zafar, a senior police official, told reporters in Rahim Yar Khan district.
Mohammad Mushtaq, a senior government official, told the private Dunya TV that 16 people had been killed and 20 wounded. The injured had been rushed to local hospitals, he added.
"We are trying to calm the situation," Mushtaq said, after angry and tearful marchers attacked a police station.
Nabeela Ghazanfar, a spokesman for Punjab police, said 25 people were wounded in the bomb blast.
There had been confusion at first as to the cause of the explosion, with one senior police official, Abid Qadri, saying it was caused when a flag from the procession hit a power wire.