58 killed, more than 150 wounded in Iraq June 13, 2012 -- Updated 0955 GMT (1755 HKT) Baghdad (CNN) -- A string of car and roadside bombs exploded in northern and central Iraq Wednesday morning, killing at least 58 people and wounding 156 others, police officials said. The attacks Wednesday come after mortar rounds landed on pilgrims in northwestern Baghdad's Kadhimiya Shiite neighborhood Sunday leaving at least seven people dead and 20 others wounded. Al-Kadhim is among 12 revered imams in Shiite Islam. Wednesday's attacks are the deadliest since February 23, 2011 when nearly 50 people were killed and more than 200 were wounded. A similar number people died on March 20 of this year in attacks across the country. Since the U.S.-led invasion of Iraq in 2003, thousands of Shiite pilgrims have been killed and wounded by Sunni extremists, including groups like al-Qaeda in Iraq. While the attacks continue, violence in Iraq is down dramatically since the peak of sectarian violence between 2005 and 2007. During May, 132 people were killed and 248 others were wounded in violence across the country.