U.S. senators on Thursday cleared a first hurdle to a sweeping foreign aid package — including a $60 billion lifeline for Ukraine — although opposition from right-wing allies of Republican presidential candidate Donald Trump means final passage remains far from guaranteed.

The procedural vote to at least consider the bill marked a stunning about-face by Senate Republicans.

Until now they had refused to renew funding for Ukraine's fight against Russian invasion if Democrats didn't also agree to stringent new curbs on a record surge of undocumented migrants across the U.S.-Mexican border.