Iran nuclear talks 'tough, direct and serious': US

(WASHINGTON) - Talks in Oman on Iran's suspect nuclear program, which ran into an unexpected second day between world powers and Tehran, were "tough, direct and serious," a US official said Monday.

State Department spokeswoman Jen Psaki said the United States remains "very focused on making progress and seeing if we can get a deal done before the deadline."

"There's still time to do so," she told reporters in Washington.

With a November 24 deadline looming for a comprehensive agreement, US Secretary of State John Kerry and Iran's Foreign Minister Mohammad Javad Zarif met Sunday and again on Monday in Muscat with the EU negotiator Cathy Ashton.

The talks will now move to a lower level between political directors from Iran and the group called the P5+1 -- Britain, China, France, Germany, Russia and the United States.

They will meet in Oman "for a yet to be determined amount of time," Psaki added.

The talks had initially been set to only take place on Sunday, but Kerry's schedule had been planned to allow for additional time "if we thought there was a reason for him to stay a little bit longer."

Kerry "wouldn't have stayed had he felt it wasn't productive to continue to stay," she added.

US President Barack Obama said Sunday that a "big gap" remains on how the West can have "verifiable, lock-tight assurances" that Iran cannot obtain a nuclear weapon.

"We may not be able to get there," Obama told CBS television's "Face the Nation."

Obama said US, UN and European sanctions against Tehran would be "slowly reduced" if Tehran meets its obligations under any agreement.

Iran denies it is seeking to develop a nuclear bomb and says its nuclear program aims to produce atomic energy to reduce the country's reliance on fossil fuels, requiring a massive increase in its ability to enrich uranium in the coming years.