[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2008/images/11/05/art.boiraq1105.gi.jpg caption="Gen. David Petraeus took Sen. Barack Obama on an aerial tour of Baghdad in July when Obama visited the country."]
WASHINGTON (CNN) - The U.S. military will reduce the number of troops in Iraq this month as violence has dropped and Iraqi security forces have shown vast improvements, senior military officials told CNN Wednesday.
The military said it is sending home two brigades and not replacing one of them this month, dropping the number of brigades in Iraq from 15 to 14. A brigade has about 3,000 troops.
There are currently about 152,000 U.S. troops in Iraq.
The 2nd Brigade of the 101st Airborne Division was scheduled to leave Iraq in February 2009, but a late November departure will cut short by two months its 15-month tour.
The second unit, the 3rd Brigade of the 101st, is scheduled to leave this month and will not be replaced, according to Pentagon officials.
Army officials said that several other units will be returning early because of positive security situations on the ground in Iraq. However, current plans are to eventually replace those units, they said.
Early departures and not replacing forces could be the start of a trend that could allow President-elect Barack Obama to fulfill his campaign pledge to reduce the number of combat brigades in Iraq by roughly one a month in his first 16 months in office.