Iraqi security officials have raised the death toll from Thursday's twin bomb attack in Baghdad to at least 68.

Police said more than 120 others were wounded when the bombings went off within minutes of each other, destroying shops and cars in the Karrada neighborhood in the Iraqi capital. No one has claimed responsibility for the attacks.

A senior U.S. military officer in Baghdad, Colonel Allen Batschelet, described the attack in a statement as a senseless act of violence directed against the Iraqi people.

The attacks occurred despite an overall drop in violence since the U.S. military sent 30,000 extra troops to Iraq last year.

The U.S. military added that some 2,000 American soldiers are being withdrawn from Iraq and will not be replaced. The soldiers were part of the extra troops sent to Iraq last year to help stop the sectarian violence that had the country on the verge of civil war.

The U.S. military also announced that coalition forces killed four terrorists and detained 26 others in raids targeting al-Qaida fighters in central and northern Iraq.

The military said coalition forces detained four suspects linked to a criminal militia that was not honoring a cease-fire pledge by radical Shi'ite cleric Moqtada al-Sadr.

Last month, al-Sadr extended for another six months a cease-fire between his Mahdi army militia and U.S. and Iraqi forces. U.S. officials say the cease-fire has been key to reducing violence in Iraq by 60 percent since June.

Some information for this report was provided by AFP, AP and Reuters.