Pakistani authorities say a bomb has hit a bus carrying Shi'ite Muslims in the southern city of Karachi, killing at least one person.

The blast comes a day after suspected Sunni militants shot and killed 22 Shi'ites who were traveling on buses in Pakistan's northwestern Mansehra district.

Officials say the bus was carrying Shi'ites on their way to an annual rally marking solidarity with the Palestinians when the bomb exploded in Karachi. At least 11 people were wounded in Friday's blast.