U.S. President Barack Obama has a tough decision in front of him when deciding on whether or not to ramp up air strikes against the Islamic State.

The U.S. has already started drone surveillance over Syria, monitoring the positions and movements of the Islamic State militant group, but the president has not authorized any attacks in the country.

Earlier this month, Obama OK'd air strikes on the Islamic State in Iraq, which have helped Kurdish fighters regain lost territory. But air strikes in Syria pose significant challenges, according to a Reuters report.

Those challenges include gaps in intel on potential targets, worries about Syria's air defense system and fears that Islamic State forces may have anti-aircraft weapons.

Last week, the Islamic State posted a video depicting the beheading of American journalist James Foley, prompting The Pentagon to start laying out options for an assault.

According to military sources, nearly all options carry with them a problem.

"There are all kinds of downsides and risks that suggest air strikes in Syria are probably not a great idea," said Aaron Miller, a former Middle East adviser to past U.S. administrations. "But that doesn't mean they won't happen anyway."

The U.S. relied on intel from Iraqi and Kurdish forces in prepping for air strikes on the Islamic State in Iraq. The intel coming out of Syria is not as reliable.

Complicating matters further is Syria's Russian-made air defense systems, which are largely still intact despite the ongoing civil war. Some of those defenses have fallen into Islamic State hands, said Eric Thompson, senior strategic studies analyst at the Center for Naval Analyses.

Syria has asked for help from the U.S. and others in the international community to help the country fight the Islamic State, which over the weekend seized a Syrian airbase in the northeastern Raqqa province.

The U.S. has said that if it decides to launch air strikes in Syria, it would not be coordinating efforts with the Syrian government, The Washington Post reported. Syria has said a unilateral U.S. attack would be seen as an act of agression.