**At least three people have been killed in a bomb attack on a religious procession in the southern Pakistani city of Karachi, officials say.**Television footage showed a large plume of smoke over the site of the blast and ambulances rushing to the scene.
Pakistan’s security forces have been on high alert as Muslims have been marking the holy day of Ashura.
On Sunday at least eight people died when a suicide bomber attacked a Shia march in Pakistan-administered Kashmir.
“We are trying to ascertain whether it was a time bomb or a suicide attack, but it is a terrorist attack,” police officer Abdul Wahid Khan told Reuters news agency.
Hundreds of civilians have been killed in bomb attacks in recent months as Pakistan’s army pursues an offensive against Taliban militants in South Waziristan and surrounding areas.
Pakistan also has a long history of violence between Sunni and Shia Muslims.