Syrian militants backed by different arms of the US government have fought just outside Aleppo—a recent headache highlighting the difficulty of intruding on a disastrous war, the LA Times reports. Backed by the Pentagon, the Syrian Democratic Forces in February pushed the CIA-armed Knights of Righteousness out of the town of Marea, just north of Aleppo, according to rebel leaders and US officials. Similar battles have ensued in Aleppo and a town called Azaz, where supplies are moved and rebel fighters transported, rebels say. "Any faction that attacks us, regardless from where it gets its support, we will fight it," explains Maj. Fares Bayoush, a leader of Knights of Righteousness.
"It is an enormous challenge," says Rep. Adam Schiff, who notes that battles between US-backed fighters is "a fairly new phenomenon." Rebels are already known to fight each other around Aleppo in northern Syria, where ethnic tensions have long existed between Turkmen, Arabs, and Kurds. The Syrian Democratic Forces consist mainly of Kurdish units mixed with a few Arabs to keep it "from looking like an invading Kurdish army," the Times says. The SDF scored a major victory in February by taking the town of Al-Shadadi in Hasakeh province from ISIS, Yahoo News reports. Meanwhile, the CIA has a center in Turkey where it arms Syrian rebels with TOW antitank missiles to use against the Assad government. (Read more Syrian civil war stories.)