'Saudis have not treated US fairly'

President Donald Trump has complained that US ally Saudi Arabia was not treating the United States fairly and Washington was losing a "tremendous amount of money" defending the kingdom.

"Frankly, Saudi Arabia has not treated us fairly, because we are losing a tremendous amount of money in defending Saudi Arabia," he said.

Trump's criticism of Riyadh was a return to his 2016 election campaign rhetoric. "Nobody's going to mess with Saudi Arabia because we're watching them," Trump told a campaign rally in Wisconsin a year ago. "They're not paying us a fair price. We're losing our shirt."

The United States is the main supplier for most Saudi military needs, from F-15 fighters to control and command systems worth tens of billions of dollars in recent years, while American contractors win major energy deals.

Saudi officials could not immediately be reached for comment on Trump's latest comments.

Meanwhile, ninety-nine days into office President Donald Trump rallied his "friends" from the National Rifle Association on Friday, telling the hugely powerful US gun lobby the "assault" on their right to bear arms is over.

"I will never, ever infringe on the right of the people to keep and bear arms," Trump vowed in Atlanta, Georgia at the annual convention of the NRA, which pumped cash into his maverick election campaign in 2016.