When President Obama secretly authorized the Central Intelligence Agency to begin arming Syria’s embattled rebels in 2013, the spy agency knew it would have a willing partner to help pay for the covert operation. It was the same partner the C.I.A. has relied on for decades for money and discretion in far-off conflicts: the Kingdom of Saudi Arabia.
Since then, the C.I.A. and its Saudi counterpart have maintained an unusual arrangement for the rebel-training mission, which the Americans have code-named Timber Sycamore. Under the deal, current and former administration officials said, the Saudis contribute both weapons and large sums of money, and the C.I.A takes the lead in training the rebels on AK-47 assault rifles and tank-destroying missiles.