By
"According to the reports forty people have died and 30 to 35 wounded," he said.
The wounded have been rushed to the Dera Ghazi Khan hospital, Sahu told a private television channel.
Local police chief Tasadduq Hayat told AFP by telephone that the bomb exploded outside the shrine.
"It was a bomb blast and it is not clear if it was a suicide attack" he said.
More than 30 people were wounded, he said, adding that details about the death toll were being collected.