The United States does not appear to have clear-cut legal authority to protect Syrian rebels it trains from attack by forces loyal to Syrian President Bashar al-Assad, even under new war powers, U.S. Defense Secretary Ash Carter said on Wednesday.

Still, Carter told Congress, a final determination had not yet been made.

The remarks underscore the deep uncertainty surrounding a fledgling U.S. military-led training program expected to get under way in the coming weeks, first in Jordan, then at training sites in Turkey, Saudi Arabia and, later, Qatar, with the goal of training upwards of 5,000 fighters a year. […]