As Baghdad stood in the cross-hairs of advancing al-Qaeda forces Wednesday, the Obama administration branded the exodus of Iraqis from terrorist territory as a “humanitarian crisis” while some members of Congress called it a monumental failure in the war on terror.

Half a million Iraqis were fleeing militants from the Islamic State in Iraq and the Levant (ISIL or ISIS), the successor to al-Qaeda in Iraq, after the rapid seizures of Mosul, Baiji and Tikrit — the hometown of Saddam Hussein. In an audio recording, ISIS vowed to take Baghdad, though Kirkuk’s fall appeared next on their list.

Iraqi officials told the Guardian that upwards of 30,000 soldiers — two divisions — simply fled from about 800 ISIS fighters. The militants joyfully seized U.S.-made Humvees and BlackHawks, according to numerous reports and photographic evidence, as well as SCUDs and Howitzers, and transported many back to Syria to share with extremists there.

Militants also bulldozed the border line between Syria and Iraq, celebrating this breaking of an international border as the beginning of the caliphate.

“The United States is deeply concerned about the continued aggression of ISIL in Iraq,” White House spokesman Josh Earnest told reporters aboard Air Force One en route to a commencement address and fundraiser in Massachusetts. “In addition to the violence in Mosul, we’ve seen the reports and are closely following the ongoing attacks and violence in the Baiji and Tikrit areas, and other parts of northern Iraq. The deterioration in security is rapidly becoming a humanitarian issue and requires a coordinated response by Iraqi leaders from across the country to halt the advances ISIL has made and regain control of territory currently in ISIL’s hands.”

Earnest condemned the “despicable” attack on Turkish consulate officials in Mosul. Militants seized 49 Turkish diplomats and family members and brought them to the city’s ISIS headquarters.

“I think that there’s no doubt that the situation has deteriorated even in the last 24 hours. It’s something we’re concerned about. And we’ve been in touch with the government of Iraq about what we can do to support them as they try to address this security threat,” he continued, proceeding to tout the Counterterrorism Partnership Fund proposed in President Obama’s recent foreign policy speech at West Point.

Earnest also held up the administration as “very attentive to the wide range of humanitarian needs that are pretty severe in the region right now.”

He said the White House considers the fall of Iraq a “serious threat.”

“Core al-Qaeda had repeatedly and publicly vowed to attack the United States homeland. The threat in the region that we’re talking about now appears to be somewhat different, but it’s one that we are watching very carefully for a variety of reasons — because they’ve proven to be very violent, because they’ve demonstrated a willingness to consider targeting American interests and American allies.”

Sens. John McCain (R-Ariz.), Lindsey Graham (R-S.C.) and Kelly Ayotte (R-N.H.), though, called the fall more than just a deteriorating situation: “Our worst fears about Iraq are being realized today.”

“The black flags of al-Qaeda are flying over Mosul, Iraq’s second largest city, just as they do over Fallujah. Al-Qaeda affiliated militants are now pressing their offensive into other parts of western Iraq and possibly beyond. This growing threat to our national security interests is the cost of President Obama’s decision to withdraw all of our troops from Iraq in 2011, against the advice of our commanders and regardless of conditions on the ground,” the trio said in a statement.

“Unfortunately, the president is now making the same disastrous mistake in Afghanistan, increasing the risk that al-Qaeda and its terrorist allies will return there just as they are in Iraq,” the senators added. “It is not too late for the president to reverse this catastrophic decision and instead make any withdrawal of U.S. forces after this year contingent on conditions on the ground.”

“At the same time, we call on the president to explain to Congress and the American people how he plans to address the growing threat to our homeland and our national security interests posed by the rapidly expanding al-Qaeda safe haven in Iraq and Syria.”

The Senate Armed Services Committee, of which McCain, Graham and Ayotte are members, called a closed-door briefing for Thursday morning to hear an update on the situation from the Defense Intelligence Agency and Pentagon officials.