Republican senators on Saturday blamed the Obama administration for Al Qaeda affiliates over-running parts of Iraq, including the city of Fallujah, which the United States secured before President Obama removed all U.S. forces from that country in 2011.

Sen. John McCain, Arizona, and Lindsey Graham, South Carolina, called the recent turn of events “as tragic as they were predictable” and suggested Obama misled Americans into believing that Iraqi leaders wanted U.S. forces out of their country.

“While many Iraqis are responsible for this strategic disaster, the administration cannot escape its share of the blame,” the senators said in a joint statement. “When President Obama withdrew all U.S. forces … over the objections of our military leaders and commanders on the ground, many of us predicted that the vacuum would be filled by America's enemies and would emerge as a threat to U.S. national security interests. Sadly, that reality is now clearer than ever.”

The Al Qaeda-affiliated fighters took over Fallujah on Friday after a bloody three-day battle, raising their flag over government buildings as a sign of victory, according to The Washington Post.

At least eight people were killed and dozens injured Friday night as the Iraqi army tries to regain control of the city. The army, which lobbed mortar bombs in its response, has been joined in the fray by tribesmen from Ramadi, a Sunni stronghold.

U.S. forces secured Fallujah in 2004 after one of the deadliest battles of the Iraq war. Fallujah became notorious among Americans when insurgents in 2004 killed four American security contractors and hung their burned bodies from a bridge.

After the recent takeover by Al Qaeda-tied fighters, the Obama administration on Saturday called the attacks barbaric and said it is working with the Iraqi government and the tribal leaders.

“We are … concerned by efforts of the terrorist Al Qaeda/Islamic State of Iraq and the Levant to assert its authority in Syria as well as Iraq,” said State Department spokeswoman Marie Harf. “Their barbarism against civilians of Ramadi and Fallujah and against Iraqi Security Forces is on display for all to see.”

Major Sunni tribes turned against Al Qaeda before the American withdrawal at the end of 2011. But they do not support the Shiite-led government in Iraq, creating an odd alliance in the battle against militants.

“The administration's narrative that Iraq's political leadership objected to U.S. forces remaining in Iraq after 2011 is patently false,” said McCain and Graham, military hawks with an active interest in Middle East affairs. “We know firsthand that Iraq's main political blocs were supportive and that the administration rejected sound military advice and squandered the opportunity to conclude a security agreement with Iraq."

On Friday, the Al Qaeda affiliates tried to win over the population in Fallujah with a militant commander appearing among worshippers holding Friday prayers in the main city street, proclaiming that his fighters were there to defend Sunnis from the government, a resident said.

There have been no reports on the total number of people injured or killed in the fighting that started earlier this week.

The overrunning of Fallujah and Ramadi, another Sunni stronghold, by Al Qaeda’s Iraqi branch in the Sunni heartland of western Anbar provinces is a blow to the Shiite-led government of Prime Minister al-Maliki. His government has been struggling to contain discontent among the Sunni minority over Shiite political domination that has flared into increased violence for the past year.

Anbar province, a desert area on the borders with Syria and Jordan, has almost an entirely Sunni population. The area served as the heartland of the Sunni insurgency that rose up against American troops and the Iraqi government after the 2003 U.S.-led invasion that toppled Saddam Hussein. Authorities earlier this week arrested a senior Sunni politician and dismantled a months-old sit-in in Ramadi sparking anger among Sunnis.

In an effort to ease tensions, al-Maliki pulled the military out of Anbar cities to transfer security duties to local police, a top demand of Sunnis who see the army as a tool of al-Maliki’s rule. Al Qaeda militants then erupted in Fallujah and Ramadi overrunning police station, driving out security forces and freeing prisoners.

“Thousands of brave Americans who fought, shed their blood, and lost their friends to bring peace to Fallujah and Iraq are now left to wonder whether these sacrifices were in vain,” said McCain and Graham, who argued the administration’s failure in Iraq has been compounded by its failed policy in Syria.

That country is involved in a years-long civil war in which tens of thousands have been killed or driven from their homeland, which the senators say has resulted in a regional conflict that now threatens U.S. national security interests.

The senators also called on Obama to learn from the Iraq experience and promptly decide on the troop levels needed to secure U.S. national security interests in Afghanistan and to keep out Al Qaeda and its terrorist allies.

The Associated Press and Reuters contributed to this report.