US Secretary of State John Kerry will head to the Gulf in August seeking to allay fears over the Iran nuclear deal, as Saudi Arabia Thursday warned Tehran against any further "mischief" in the region.

Back at work only days after an 18-day negotiating marathon to seal the unprecedented accord, Kerry met Saudi Foreign Minister Adel al-Jubeir, the beginning of a charm offensive designed to win over the many doubters in the United States and abroad.

"All of us in the region want to see a peaceful resolution to Iran's nuclear program," Jubeir said after their talks.

He welcomed a deal with a "robust and continuous inspections regime to make sure Iran does not violate the terms of the agreement," adding it should also have an effective and quick "snapback" mechanism that allows for sanctions to be quickly reimposed if Tehran violates Tuesday's accord.

Under the deal, Iran will win relief from crippling sanctions in return for dismantling and mothballing much of its nuclear industry so it cannot quickly develop an atomic bomb.

"We hope that the Iranians will use this deal in order to improve the economic situation in Iran and to improve the lot of the Iranian people, and not use it for adventures in the region," Jubeir said.

But he warned "if Iran should try to cause mischief in the region we're committed to confront it resolutely."

Iran stands accused of supporting Shiite Huthi rebels in Yemen who overran the capital and parts of the country, forcing the Western-backed President Abedrabbo Mansour Hadi and his government into exile in Riyadh.

Saudi-led warplanes have been waging air strikes against the rebels since March, helping to force the militia into retreat with ministers from Hadi's exiled government now preparing to visit the southern city of Aden to assess the damage.

Majority Sunni Gulf countries have remained wary of the US overtures to arch-foe Iran, believing the nuclear deal will only embolden Tehran's Shiite leaders.

But Kerry said he will travel to the Gulf to brief leaders on the hard-won accord.

"I will be meeting with the entire GCC and giving them a full briefing, download, answering any questions they have on August 3," Kerry said.

The Saudi minister said the meeting with the Gulf Cooperation Council would take place in Doha.