insurgency there, officials told Congress on Wednesday, The Wall Street Journal Newspaper said in news briefed by “Shafaq News”.

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.

Mr. McGurk and Elissa Slotkin, a Pentagon policy official, emphasized the continued threat that the extremist group Islamic State poses to the U.S. and its allies. Mr. McGurk spent the past seven weeks in Iraq and described the group as a "full-blown army," not just a terrorist organization, and said it was worse than al Qaeda.

Lawmakers from both parties expressed frustration that the U.S. didn't do more to help Iraqi forces and Syrian groups fighting extremists sooner.

Lukman Faily, Iraq's ambassador to the U.S., said the U.S. was sending mixed signals to Baghdad about its intentions regarding military support. "If Iraqis don't believe that meaningful U.S. assistance is forthcoming, then they will not have enough incentive to adopt the political reforms that America is urging," he said in a statement to The Wall Street Journal.

Rep. Ed Royce (R., Calif.), chairman of the committee, said the Obama administration denied repeated requests for drone strikes from the Iraqi government, which he said Iraqi leaders had made since last August. Mr. McGurk said the U.S. received a formal request for support from Iraq in May.

Mr. McGurk said the U.S. has continued to study the possibility of drone strikes in Iraq. When asked about assessments of Iraqi forces on the ground, Ms. Slotkin said there are some "very capable units" that could assist the U.S. with airstrikes, should President Barack Obama pursue that option.

However, both Mr. McGurk and Ms. Slotkin said military support alone wouldn't sufficiently address instability in Iraq, and that the formation of a new Iraqi government would be key to lessening the Islamic State's strength.

Ms. Slotkin said a "strong, capable" federal government in Baghdad would be the best defense against threats from the Islamic State and strong Iranian influence in the region.

U.S. officials have been pushing for the formation of a new government that can convincingly move away from exclusionist policies that Washington believes have been in effect under Prime Minister Nouri al-Maliki.

Of the U.S. troops sent to Iraq, 475 are providing security for the American Embassy in Baghdad.

The Obama administration's priorities in Iraq are improving U.S. intelligence, supporting the formation of a new government and aiding Iraqi forces in repulsing the Islamic State, which has taken control of much of Iraq, Mr. McGurk said in the hearing Wednesday.