The US president has vetoed resolutions in Congress to block the sale of $8.1bn (£6.5bn) worth of weapons to Saudi Arabia and the United Arab Emirates.
Donald Trump said the three resolutions "would weaken America's global competitiveness" and damage its relationship with its allies.
It comes after both chambers of Congress voted to prevent the sale.
Some members of Congress said they feared the weapons could be used on civilians in the Yemen conflict.
They have condemned Saudi Arabia's role in Yemen as well as last year's murder of Saudi journalist Jamal Khashoggi.
BBC
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