A car bomb exploded in a parking lot on the perimeter of Baghdad's heavily guarded international airport complex on Sunday, wounding five people.
The blast occurred at the first point where passengers gather to be searched before boarding airport taxis to the terminal building, which is several kilometres away, the sources said.
It was not immediately clear who was responsible for the attack.
OPEC oil producer Iraq is facing its worst crisis since a U.S.-led invasion toppled Saddam Hussein in 2003.
Islamic State militants who swept through the north of the country in June and hold large parts of western Iraq have claimed responsibility for suicide bombings in Baghdad and elsewhere.
The presence of the Sunni insurgents has fueled sectarian tensions, deepening a security crisis and drawing U.S. air strikes after Western hostages were beheaded.
The air campaign, which includes neighbouring Syria, has helped prevent any further Islamic State advances in recent weeks.
The United States' top military officer told American troops on a surprise visit to Baghdad on Saturday that the momentum in the battle with Islamic State was "starting to turn", but predicted a drawn-out campaign lasting several years.