US Secretary of State John Kerry has said the window for diplomacy over Iran's nuclear program is "cracking open" ahead of new negotiations between Iran and the five permanent United Nations Security Council members and Germany.

But one of Iran's top negotiators for the talks, planned for Tuesday and Wednesday in Geneva, said Tehran would not send any of its enriched uranium abroad as part of any deal to ease sanctions over its contested program.

"I want you to know that our eyes are open, too," Kerry said on Sunday in comments made via satellite to the American Israel Public Affairs Committee summit in California.

"While we seek a peaceful resolution to Iran's nuclear programme, words must be matched with actions. In any engagement with Iran, we are mindful of Israel's security needs."

Iranian negotiator Abbas Araghchi's comments were published on Sunday on Iranian state television's website. He was quoted saying "shipping the material abroad is our red line. We do not allow shipment of even one gram of uranium from Iran.''

"We will negotiate about the volume, levels and the methods of enrichment but shipping out the (enriched) material is a red line for Iran."

Enrichment endgame

The comments of the chief negotiator come ahead of new negotiations between Iran and the five permanent United Nations Security Council members and Germany, planned for Tuesday and Wednesday in Geneva.

The negotiations with the group, collectively known as the P5+1, come as international sanctions over the nuclear program continue to batter Iran's economy.

It will be the first such negotiations since President Hassan Rouhani, a reputed moderate, took office in August. Rouhani has pledged to engage constructively to resolve the decade-long dispute over Iran's nuclear drive and ultimately secure the lifting of crippling Western sanctions.

A source close to Iran's negotiators told the official IRNA news agency they would submit to the powers "a clear path" for the talks, and include a timetable and a framework with "specified first and last steps."

ISNA news agency cited Iranian diplomats as saying "recognition of the right to enrichment on Iranian soil" was the endgame for the talks, not a precondition as in the past.

The Iranians have insisted their nuclear program is peaceful and that they only seeks reactors for energy and medical use, while the West suspects Iran seeks to make a nuclear weapon. Iran has not publicly specified what measures it could take to satisfy Western concerns.

Source: Agencies