Story highlights Pentagon considering when to recommend authorizing drone strike agains ISIS leader

Any mission to kill ISIS leader Abu Bakr al-Baghdadi would need Obama's approval

Al-Baghdadi has $10 million bounty on his head through Reward for Justice program

The Pentagon is considering under what circumstances it will recommend President Barack Obama authorize the use of a missile-equipped drone to kill the leader of Islamic State in Iraq and Syria , Abu Bakr al-Baghdadi, CNN has learned.

Any such mission to kill al-Baghdadi would have to be approved by Obama, according to several defense officials CNN has spoken to at length. All of the officials have direct knowledge of the intelligence gathering efforts in Iraq, but declined to be named due to the sensitivity of the information.

"He is a person of great interest to us," one defense official told CNN. If the U.S. military were to recommend a drone strike against al-Baghdadi, there would have to be specific and detailed intelligence showing his location at the moment of a strike and intelligence to assure that civilians would not be at risk. In order to launch a kill mission, the U.S. has to demonstrate the target poses a threat to the U.S. Al-Baghdadi's ISIS organization does threaten the U.S. Embassy and U.S. citizens in Iraq, according to U.S. officials.

It is also possible the U.S. could turn the information over to the Iraq government for it to conduct a capture or kill mission against the ISIS leader on its own. Another point of consideration would be the impact of a U.S. strike on the situation in Iraq and whether the U.S. would be seen by Sunnis as siding with the Shiite-led government.

Al-Baghdadi already has a $10 million bounty on his head from the U.S. government's Reward for Justice program , which offers multi-million dollar rewards for information leading to the capture of certain high value terrorists around the world. Last week, al-Baghdadi made a very public appearance at a prominent mosque in northern Iraq. Eyewitnesses said he drove up to the mosque in a large convoy and remained surrounded by civilians.

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But U.S. officials said capturing al-Baghdadi would be difficult because the U.S. military does not have combat troops on the ground in either Iraq or Syria, where al-Baghdadi and ISIS are known to operate. In addition, any covert capture mission by U.S. special forces or law enforcement inside Iraq could be seen as violating Iraq's sovereignty, though such a mission remains possible.

That means al-Baghdadi is essentially on a U.S. "kill list" even though such a list in Syria and Iraq has never been openly acknowledged. Under U.S. policy, lethal drone attacks are generally authorized when there is no reasonable possibility of capturing a suspect.

The possibility comes as part of the U.S. military effort to gather intelligence on so-called "high value targets" in Iraq and continues to collect intelligence for targeting airstrikes in Iraq. The targets fall into three categories, the officials said. They include information for striking "high value targets" like al-Baghdadi; protection of key infrastructure such as the Haditha Dam; and blunting major ISIS offensives against Baghdad. Airstrikes by either drones or manned aircraft would have to be approved by the President.

There are also electronic intercepts being conducted, according to one U.S. official.

In recent days the U.S. military has again increased its reconnaissance missions over Iraq from the 30 missions a day it was conducting. "It's up around 50 right now. And it's stayed there for a good many days," according to Rear Adm. John Kirby, Pentagon press secretary.