The U.S. has increased surveillance efforts and has sent additional military advisers to Iraq to better aid national forces and understand the expanding extremist insurgency there, officials told Congress on Wednesday.

Since extremists seized control of Mosul in June, U.S. surveillance flights over Iraq have increased to nearly 50 a day, up from one flight a month, said Brett McGurk, the deputy assistant defense secretary for Iraq and Iran, in testimony before the House Foreign Affairs Committee.

The Pentagon said 20 additional military advisers recently arrived in Iraq, bringing total U.S. military personnel there to 825. Pentagon spokesman Col. Steve Warren said there are now 90 advisers working with Iraqi military forces, assessing their capabilities, and 160 Americans are assigned to joint operation centers in Baghdad and Erbil. […]