Officials in Iraq say a bomb planted on a street full of shoppers in the capital, Baghdad, has killed three people and wounded five. Police officers say the explosion took place in the capital’s predominantly Shiite neighborhood of al-Ameen on Friday morning. Health officials confirmed the casualty figures. All officials spoke on condition of anonymity because they were not authorized to talk to journalists. No one immediately claimed responsibility for Friday’s attack, but Sunni insurgent groups have stepped up attacks across the country since last year, in a bid to undermine the Shiite-led government. The uptick in violence comes at a crucial time, as Iraqis prepare to hold parliamentary elections on April 30, the first such vote since U.S. forces left Iraq in 2011.