A handful of moderate Republicans in the US House of Representatives forced a vote to extend healthcare subsidies used by millions of Americans that are set to expire at the end of the year.
The House vote is slated for Wednesday evening but if it passes - which is expected - it will face an uphill battle in the Senate.
The surprise vote is a last-ditch effort by some Republicans to put on record their support for extending healthcare subsidies in some form - ahead of their expiration and expected steep rise in premiums for millions.
Without the subsidies, insurance premiums through the Affordable Care Act (ACA), also known as Obamacare, are on course to more than double.
The moderate Republicans forced the vote using a mechanism called a discharge petition, which with enough support, allows members to bring measures to the floor for a full vote.
