Washington, Nov 22 (IANS): The world's major powers and Iran are racing against time to reach a deal over Tehran's nuclear programme, with another extension of the negotiations not being the focus.

White House spokesman Eric Schultz Friday said Secretary of State John Kerry was in Vienna, Austria, for talks in his last-ditch efforts to close the "remaining gaps", as the Nov 24 deadline is fast approaching, reported Xinhua.

"We are pressing hard. We are running against the clock. Obviously the deadline is Monday, and our folks there are working furiously to meet it," Schultz told reporters aboard Air Force One en route to Las Vegas, Nevada.

"We're going to race against the clock to get this done," he added.

Hope for a comprehensive deal by Monday is fading, as gaps remain on some key issues, which include the size and scope of Iran's nuclear programme, particularly the number of centrifuges Iran will be allowed to operate, and the nuclear-relevant sanction relief for Iran.

"Serious gaps do remain, and throughout the negotiations, the P5 1 have put forth proposals that are consistent with our core objectives and consistent with Tehran's expressed desire for a viable civilian nuclear program," Schultz said.

Iran and the six powers (Britain, China, France, Russia, the United States plus Germany) agreed in July to extend their nuclear talks for another four months till Nov 24, as they could not narrow down significant gaps on core issues during the past six months.

The two sides began their latest round of talks in Vienna Tuesday.