BAGHDAD — A car bomb detonated a fuel tank in Iraq’s second-largest city, Basra, on Saturday, spreading fire through a crowded market, Interior Ministry officials said, in the worst attack of the day that marked five months since Iraqis voted for a new government that has yet to be created.

The death toll of the Basra bombing rose to 43 by Sunday morning, according to an official at the Interior Ministry, and another 185 were wounded. Also Sunday, a parked car filled with
explosives detonated outside a passport office -- the first reports put the casualty toll at eight killed and 50 wounded.

The U.S. military also said Sunday that an American soldier was killed in southern Iraq on Saturday.

For weeks, American and Iraqi officials have said they expect violence to grow as the American military reduces the number of its troops to 50,000 from about 64,000 by the end of the month. The withdrawal comes amid anxiety in the streets over the political paralysis, which could last months more, and growing fears that insurgents are trying to reorganize in regions like Baghdad and Falluja, where they long had a presence.