Highly anticipated talks with Iran over its nuclear program fell apart Saturday, with no new date set for another meeting.

Iran met with representatives of the five permanent members of the U.N. Security Council plus Germany in Istanbul, but wouldn't budge after claiming its negotiators went "far and beyond what was expected of us."

The European Union's foreign policy chief, Catherine Ashton, told reporters that Tehran had sought preconditions including an end to U.N. sanctions before moving forward.

"We had hoped to have a detailed and constructive discussion of those ideas," she said. "But it became clear that the Iranian side was not ready for this unless we agree to preconditions related to enrichment and sanctions."

On Friday, State Department spokesman P.J. Crowley refused to give reporters a "halftime report" on the talks but said they were already envisioning a process that went beyond one meeting.

"If you want to follow my football analogy, for the NFL, for example, there are 16 games in a season," he said at the daily press briefing. "After the second game, you don’t decide whether a team is in the Super Bowl or not. We would envision that in order to resolve all of the questions regarding Iran’s nuclear program, it is going to take a lengthy process, not one or two meetings, to answer all those questions."

Crowley said Washington is being "sober and realistic" about the process.

Iran's top negotiator, Saeed Jalili, told reporters Saturday that "talks can be useful, successful and progressive only when they are based on a common logic."

"When you speak of cooperation, you must avoid whatever causes confrontation and animosity towards a nation, when you speak of cooperation on common points, you must surely respect the nations' rights," Jalili said, according to Iran's semi-offical Fars News Agency.

Iran's foreign ministry said Saturday that all countries, even North Korea, should have access to nuclear technology.