Trump uses veto power in border emergency declaration

US President Donald Trump has vetoed a bid from Congress to oppose his declaration of a national emergency at the US-Mexico border.

Lawmakers had earlier passed a rejection resolution of Trump's pledge to build a border wall.

However they'll now need a two-thirds majority in both chambers to override the veto.

Trump said as president, "the protection of the nation" is his highest duty.

It's the first veto Trump's presidency.