https://consortiumnews.com/2015/10/01/should-us-ally-with-al-qaeda-in-syria :

On Oct. 2, 2014, Biden told an audience at Harvard’s Kennedy School: “our allies in the region were our largest problem in Syria … the Saudis, the emirates, etc., what were they doing? They were so determined to take down Assad and essentially have a proxy Sunni-Shia war, what did they do? They poured hundreds of millions of dollars and tens of thousands of tons of military weapons into anyone who would fight against Assad, except the people who were being supplied were Al Nusra and Al Qaeda and the extremist elements of jihadis coming from other parts of the world.” [Quote at 53:20 of clip.]