Former US Ambassador to Syria Robert Ford suggested on Thursday that Washington is aware its aid to Syrian rebels is benefiting an al-Qaeda affiliate.

Ford made the comments in reference to insurgents’ cooperation with the group, Jabhat al-Nusra.

“The days of us looking the other way are finished,” he said, according to McClatchy reporter Hannah Allam. “Cooperation with a terrorist group has political impact,” he added.

Ford also predicted that Nusra would “attack the US and our friends in Europe,” according to another journalist present.

The ex-envoy said he believes last week’s attacks in Paris will alter the conflict and should force rebels to “think about who you’re working with.”

In May, The Wall Street Journal reported that the Free Syrian Army – a beneficiary of US aid – was fighting with Nusra against the Assad government near the Israeli-occupied Golan Heights.

An FSA commander denied the charge, but the White House was reluctant to arm the group with some heavy weapons as a result, according to the WSJ.

Nonetheless, the White House asked Congress for a half billion dollars to finance and train the rebellion against Bashar al-Assad’s government. It claimed the aid would be “appropriately vetted.”

Congress greenlighted the request in September, in the context of the US war against the Islamic State in Syria and Iraq.

Ford, however, described this strategy as a “myth,” saying Assad remains rebels’ prime enemy.