Kabul (CNN) — U.S. Secretary of State John Kerry arrived in Austria on Sunday for talks with five other world powers and Iran on Tehran's nuclear program.
The participants will hold a final round of negotiations ahead of a July 20 deadline aimed at reaching a permanent deal on the future of Iran's nuclear program.
"Obviously, we have some very significant gaps still, so we need to see if we can make some progress," Kerry said in the Austrian capital, Vienna. "I really look forward to a very substantive and important set of meetings and dialogues."
The nuclear talks will include the five permanent members of the United Nations Security Council -- the U.S., UK, France, China and Russia -- and Germany.
"It is vital to make certain that Iran is not going to develop a nuclear weapon, that their program is peaceful," Kerry said.
Tehran insists its ambitions are peaceful, but the world powers fear it plans to build nuclear weapons.
"We don't see any benefit in Iran developing a nuclear weapon," Iran's Foreign Minister Javad Zarif told NBC's "Meet The Press" from Vienna.
He said Iran has a number of advantages over its neighbors, including "the fact that we have better technology," which Iran doesn't need to augment with nukes.
Kerry planned to speak in Vienna with his German counterpart, Frank-Walter Steinmeier, senior administration officials said. The foreign ministers' encounter will come amid a row over fresh spying allegations against the United States.
On Thursday, Germany's government asked America's top spy chief stationed in the country to leave.
This followed the revelation that two Germans -- one working at a German intelligence agency, the other in the Ministry of Defense -- are suspected of spying for the United States.
Kerry's stop in Austria follows an unannounced visit to Afghanistan, where divisions are growing since the country's contested presidential runoff election.
After his visit, he announced that an audit of the disputed presidential election results will begin within a day in Kabul, and the two candidates will accept its determination of who won.
The inauguration of the new president, originally scheduled for August, will be postponed during the audit of votes cast for Abdullah Abdullah and Ashraf Ghani, Kerry said. Provisional results showed Ghani ahead with roughly 56% support to 43% for Abdullah.
Both candidates have alleged vote fraud and manipulation during the runoff last month.
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