The United States officially declared its combat role in Iraq over on August 31, 2010, although several thousand troops remained in the country until all American troops were withdrawn from Iraq by December 2011; meanwhile American troops also engaged in combat with Iraqi insurgents. In June 2014, however, US forces were reinstated in Iraq due to the escalation of instability in the region and as of June 2015, the number of American ground troops totaled to 3,550. Between December 2011 and June 2014, Department of Defense officials estimated that there were 200 to 300 personnel based at the US Embassy in Baghdad.