Three years after the CIA began secretly shipping lethal aid to rebels fighting against Syrian President Bashar al-Assad, battlefield losses and fears that a Donald Trump administration will abandon them have left tens of thousands of opposition fighters weighing their alternatives, The Washington Post reports.

Among the options, say U.S. officials, regional experts and the rebels themselves, are a closer alliance with better-armed al-Qaeda and other extremist groups, receipt of more sophisticated weaponry from Sunni states in the Persian Gulf region opposed to a U.S. pullback, and adoption of more traditional guerrilla tactics, including sniper and other small-scale attacks on both Syrian and Russian targets.

Just over a year ago, the opposition held significant territory inside Syria. Since then, in the absence of effective international pushback, Russian and Syrian airstrikes have relentlessly bombarded their positions and the civilians alongside them. On the ground, Syrian government troops — bolstered by Iran, Lebanon’s Hezbollah, and Shiite militia forces from Iraq — have retaken much of that ground.

In brutal attacks over the past three weeks, they have been driven out of much of the eastern Aleppo stronghold that they have occupied since 2012.