"We're very happy the outcome of the results disappointed pundits, and exceeded beyond most expectations," said Abdel Aziz Aluwaisheg, assistant secretary general for the Gulf Cooperation Council.
Obama had "renewed the US commitment to the region, to the Gulf states" during a high-profile summit at his presidential retreat of Camp David in Maryland, Aluwaisheg told reporters.
Obama had gathered top leaders from the six GCC countries -- Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates -- for Thursday's secluded talks in the leafy woodland retreat.
"The security of the GCC states is vital to the interests of the United States," the Arab diplomat said.
And he insisted "the US is ready now to go even a little bit further," saying that already strong ties had now been elevated to that of a "strategic relationship."
Obama had sought to reassure the majority Sunni Gulf countries wary at Washington's leading role in nuclear negotiations with their regional foe and powerful rival, Shiite Iran.
Obama said the US security commitment to America's decades-old allies was "ironclad."
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And he vowed the United States was prepared to help "deter and confront an external threat to any GCC state's territorial integrity."
In a communique issued at the end of the summit, the US and Gulf nations denounced Iran's destabilizing activities in the region.
Gulf nations have been fearful that if a deal is reached with Iran by a June 30 it will only embolden the Shiite country blamed for propping up Syrian President Bashar al-Assad during the four-year civil war and for backing Huthi rebels in Yemen who have forced the president to flee to Riyadh.
They are concerned too that a deal will lead to a widening US rapprochement with Iran -- even though the two countries have not had formal ties for more than three decades.
But Obama also managed to allay these concerns, Aluwaisheg said.
"The deal is about the nuclear program, that's really what the deal is about. There's no grand bargain," he said.
"There is no abandoning of the GCC, there is no pivot to Iran."
And he offered that "if Iran moderates its behavior... then we all will pivot to Iran, but it's in the hands of the Iranian regime."