Reports coming out of eastern Syria Monday revealed that several factions within the Syrian opposition force known as the Free Syrian Army (FSA) have pledged services to the Islamic State, the group formerly known as the Islamic State of Iraq and al-Sham (ISIS). Sources and eyewitnesses said that the FSA has handed over its weapons to the Islamic State in large numbers.

The Free Syrian Army was said to be a “moderate” and “secular” force, which was used as the rationale by U.S. officials to supply the opposition force with weapons and training.

Sources told Homs, Syria-based Zaman Alwasl newspaper that several factions within the FSA, including Ahl Al Athar, Ibin al-Qa’im, and Aisha have pledged to support the Islamic State.

On Tuesday, a spokesman for the Free Syrian Army said all of the area between Deir Ez-Zor, Syria, and the Iraqi border – a 90 mile stretch – has fallen to the Islamic State. The spokesman said that they not only controlled the territory, but had also taken over six Syrian oil and gas fields, along with a major pumping station that delivers oil to both Iraq and Syria. One of the captured oil fields included the al-Omar field, capable of producing 75,000 barrels of oil per day.

In a video proclamation, leaders in the town of al-Sahil said they “decided to swear allegiance” to the Islamic State and its leader: Abu Bakr al-Baghdadi.

The Obama administration has delivered weapons, supplies, and CIA-sponsored training to the Free Syrian Army. United States intelligence analysts estimate that the U.S. has had a hand in training as many as 20,000 FSA rebels. The U.S. reportedly provided the FSA with weapons such as rockets and TOW anti-tank missiles, which were supplied through back-channels in Qatar and Saudi Arabia.

The Free Syrian Army originally formed in July, 2011, at the start of the Syrian civil war. The group was initially composed largely of defectors from Bashar al-Assad’s Syrian Armed Forces.

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