The Islamic State may be refocusing its sights on Baghdad after the extremist group overran an Iraqi military base and executed 300 soldiers Sunday amid ongoing U.S. airstrikes aimed at weakening the militants' infrastructure and resources, according to Middle East analysts. Other targeted attacks in recent weeks also suggest the militants are plotting against the Iraqi capital more than three months after international leaders first warned of the group's aspirations to take Baghdad.

The base attack came days after the militant group also know as ISIS launched 14 mortar rounds during a foiled attempt to break into the Adala Prison in northern Baghdad. ISIS also launched an attack earlier this month in Baghdad’s Iskan neighborhood that likely targeted the offices of the political group and militia, the Badr Organization, according to the nonprofit Institute for the Study of War in Washington, D.C. 

"This attack is very significant. It is the first infantry-like, complex, and penetrating attack in Baghdad city by ISIS since the fall of Mosul in June of this year," the think-tank wrote on its website. "ISIS likely carried out the attack to release some of the pressure it is facing as a result of the recent U.S. air campaign targeting its positions. The attack also signifies that, despite the heightened defenses of Baghdad in the aftermath of the fall of Mosul, ISIS is still able to carry out attacks in an area where it is unlikely to have active sleeper cells."

It's unclear if the U.S. airstrikes in Iraq have accomplished the Obama administration's stated mission to "degrade and destroy" ISIS. Some military analysts and U.S. critics have said the White House needs to send ground troops to Iraq to wipe out ISIS, while others have said the airstrikes have successfully managed to slow down the militant group's advances.  

"The U.S. has made it pretty much impossible to undertake the large-scale mobile operations that ISIS was doing earlier in the summer," said Michael Knights, who specializes in military and security affairs in Iraq for the Washington Institute for Near East Policy. "It has changed the nature of the beast."

But ISIS' goal of taking most of western and central Iraq hasn't changed since the airstrikes, said Bill Roggio, a senior fellow at the nonprofit Foundation for Defense of Democracies in Washington who focuses on Iraq and also serves as editor of the Long War Journal. While Baghdad might be out of their reach, other territories remain vulnerable, Roggio said. 

"They are just continuing their operations," he said in a telephone interview. "The airstrikes haven't stopped them from continuing to do what they have been doing all along, which is take control of territory."

ISIS has been circling Baghdad for years. The Islamic State carried out 641 operations in Baghdad in 2013, up from 371 operations in 2012, including car bombs, armed assaults and assassinations, according to the Institute for the Study of War.

ISIS gained international prominence in June when it seized northern cities such as Tikrit, Saddam Hussein's hometown, and Mosul, Iraq's second largest city, and began holding mass executions of Iraqi soldiers. At the time, military analysts predicted the Sunni militants had their sights on Baghdad. President Barack Obama responded by sending 300 military advisers to Iraq to share intelligence with Iraqi soldiers. More recently, the Obama administration began offensive airstrikes against ISIS territories near Baghdad last week in its latest effort to pushback the militant group. The U.S. has also launched airstrikes against the Islamic State and other militant groups in Syria.

The growing campaign against ISIS might have prodded the militants to refocus their efforts in Iraq, where the Islamic State has strategic territories near Baghdad, Knight said.

"Most of the people who watch Iraq say if ISIS is going to punch, it's going to be in the Baghdad area," he said in a telephone interview. "I have been surprised that it hasn't happened ... They are well positioned for that."