Updated

Police say a bomb hidden in a cement construction block has exploded in Pakistan's largest city, killing one person.

Senior police officer Farooq Awan says the blast Monday in Karachi also wounded four people.

Awan says the bomb contained 1 kilogram (2.2 pounds) of explosives and was detonated by a mobile phone.

Pakistan suspended mobile phone service throughout most of the country on Saturday and Sunday to prevent attacks against Shiite Muslims during a major religious commemoration.

Despite the ban, a pair of bombings over the weekend killed at least 13 people.

Shiites are currently observing the holy month of Muharram. Pakistani Shiites on Sunday marked the Ashoura, the most important day of the month.

Pakistan has a long history of Sunni Muslim extremists targeting Shiites, who they consider heretics.