WASHINGTON (Reuters) - US President Donald Trump's shift to Qatar has given a harsh lesson for the UAE and Saudi Arabia about investing in it to achieve their regional goals, the Christian Science Monitor reported on Thursday.

Trump's remarkable welcome to the emir of Qatar, Sheikh Tamim bin Hamad al-Thani, showed the limited influence of Saudi Arabia and the United Arab Emirates in the White House.

He was referring to the tremendous hospitality that Trump received and praised Sheikh Tamim at the White House meetings, most recently on July 9.

Trump praised relations between his country and Qatar and his friendship with the prince, and both sides confirmed their intention to strengthen their partnership, which senior US officials describe as a strategy.

In the same report, the Christian Science Monitor website quoted people close to Riyadh as saying that Saudi Arabia is increasingly betrayed and exposed after investing in the Trump administration.

"There is a growing feeling in Riyadh that the next US administration and Congress will be more aggressive toward Saudi Arabia," he said.

The UAE is looking forward to the post-Trump era and is engaged in a comprehensive public relations campaign to rebuild relations with both parties in Congress, the website said.