Secretary of State John Kerry on Sunday briefed US ally the United Arab Emirates on talks with Iran on its nuclear programme and efforts to hold Syria peace talks.

He flew in from Geneva where three days of marathon talks which stretched into early Sunday failed to produce an interim deal under which Iran would suspend parts of its enrichment programme in return for sanctions relief.

Despite leaving without an agreement after his surprise decision to re-route his 10-day Middle East tour via the Swiss city, the top US diplomat insisted western powers were "closer now" to ending the decade-long standoff with Tehran.

He dismissed the idea that a row with French Foreign Minister Laurent Fabius had derailed the talks at the last minute, while also rejecting criticism Washington was abandoning key allies.

"A number of nations -- not just the French, but ourselves and others -- wanted to make sure that we had the tough language necessary" to ensure the six powers did not do "something sloppily that could wind up with a mistake," he told NBC's "Meet the Press".

Reiterating the P5+1 group, comprising Britain, China, France, Germany, Russia and the United States, was "not in a rush," Kerry said the aim was "to lock the programme in where it is today -- in fact, set it back -- while one negotiates the full deal."

The United States wanted "to exhaust all the diplomatic remedies before we resort to the use of military force if we have to."

Kerry held dinner talks with Abu Dhabi Crown Prince Mohammed bin Zayed Al-Nahayan and Foreign Minister Abdullah bin Zayed Al-Nahayan, and was to head home to Washington on Monday at the end of an exhausting seven-nation tour.

The UAE, like its Saudi neighbours, has reacted warily to the cautious US rapprochement with Iran's reputedly moderate new president, Hassan Rouhani.

But Kerry insisted Iran would be under "tremendous pressure" to comply with a deal as "the core architecture" of oil and banking sanctions would remain.

"We are not blind, and I don't think we're stupid. I think we have a pretty strong sense of how to measure whether or not we are acting in the interests of our country and of the globe, and particularly of our allies like Israel and Gulf states and others in the region," he told NBC.

Kerry stressed there was "zero gap" between the US administration and "our commitment to our allies in the Gulf and the region."

Rifts over Syria, Egypt

Kerry will also discuss the conflict in Syria, after Washington angered regional allies by not intervening militarily following a chemical weapons attack in August that it blamed on Damascus.

"Absent a negotiated solution we don't see a lot of ways to end the violence that are implementable or palatable to us, because we don't have the legal authority, or the justification or the desire at this point to get in the middle of a civil war," he told reporters during an earlier stop in Riyadh.

In September the UAE agreed with Saudi Arabia, Jordan and France to strengthen the Syrian opposition in its battle against President Bashar al-Assad's regime.

Efforts to get a peace conference off the ground have also floundered, with the opposition saying Sunday it would not attend the talks without the support of rebel groups in Syria which have shown little interest in negotiating with the regime.

The United Arab Emirates also is due to buy $4 billion worth of US weaponry, including bunker-buster bombs, 300 SLAM-ERs and 1,200 JSOW missiles, under pending sales notified to Congress in September.

The move follows a series of US weapons deals in recent years that have bolstered the air power and missile arsenals of Gulf states, which view Iran as a menacing rival with nuclear ambitions.

The UAE also showed frustration when Washington froze part of its $1.5 billion aid package to Egypt after the military overthrew the country's first freely elected president, Mohamed Morsi, on July 3.

Last month, the UAE agreed to give Egypt's military-installed government another $3.9 billion in aid, after transferring $1 billion in July.

In a bid to mend bridges, Kerry started his marathon trip in Cairo on November 3, his first visit since Morsi was deposed. He also visited Saudi Arabia, Poland, Israel, the West Bank, Jordan and Switzerland.