Iraqi security officials say three bombs ripped through a Shi'ite neighborhood in the capital, Baghdad, late Thursday, killing at least 23 people and wounding 107 others.

Sources at three local hospitals say at least 34 people died.

Interior Ministry officials say the explosions occurred in quick succession in southwestern Baghdad. One targeted a Shi'ite mosque and two others went off near a busy market filled with people shopping ahead of the Muslim weekend, which begins Friday.

The market bombs were transported in wooden carts usually used to carry merchandise.

There was no immediate claim of responsibility.

Also Thursday, a U.S. civilian contractor died in a separate bomb attack in Baghdad. A U.S. embassy spokesman said three additional civilians were wounded in the attack, including an American national.

Iraq has been hit by a series of bombings and shootings this week.

On Wednesday, gunmen in Baghdad opened fire on a convoy carrying Iranian oil officials, wounding two Iraqi guards who were protecting them.

In another attack Wednesday, a car bomb exploded in western Baghdad, killing a passer-by and wounding at least nine other people. Four additional bomb attacks, some targeting Iraqi police patrols, wounded at least 18 people.

Two car bombs blasts in the southern city of Diwaniyah killed 25 people Tuesday. On Monday, a roadside bomb wounded seven people near a French embassy convoy in Baghdad.

Violence in Iraq has been reduced sharply from its peak in 2006 and 2007. But, recent attacks against government officials and security forces has raised concerns that violence may increase as the United States prepares to withdraw its forces from Iraq at the end of the year.