A bomb attack in Pakistan's largest city Karachi on Sunday killed at least 23 people, including women and children, and wounded 50 others, police said.
The blast hit close to an area dominated by minority Shiite Muslims, senior police official Ghulam Shabir Sheikh told AFP, though he said that the target of the attack was not immediately clear.
"At least 23 people have been killed and more than 50 injured. The bomb also badly damaged two residential buildings. Women and children were among the dead and injured," Fayaz Lughari, police chief of Sindh province, of which Karachi is the capital, told AFP.
He said the initial blast was followed by a second, but it was unclear whether or not this was also a bomb.
Ethnic, sectarian and politically-linked violence in Pakistan's financial capital killed at least 2,284 people in 2012 in the deadliest such violence for two decades, according to the independent Human Rights Commission of Pakistan.
Salman Ahmed, a spokesman for Edhi foundation rescue service, confirmed the blast and said the wounded had been taken to three different hospitals around the city.
The unrest in the city of 18 million people comes with general elections due by mid-May. The polls would mark the first democratic transition of power in Pakistani history.
Last month Pakistan's Supreme Court accused the government of doing nothing to prevent the violence.