WASHINGTON (AP) - House Democrats have introduced a resolution to block the national emergency declaration that President Donald Trump issued to fund his long-sought wall along the U.S-Mexico border.

Friday's move sets up a fight that could result in Trump's first-ever veto. It starts the clock on a constitutional clash between Trump and Democrats and sets up a vote by the full House as soon as next week.

The Democratic-controlled House is sure to pass the measure and the GOP-run Senate may adopt it as well despite Trump's opposition. Any Trump veto would likely be sustained but the upcoming battle will test Republican support for Trump's move, which even some of his allies view as a stretch - and a slap at lawmakers' control over the federal purse.