Iran's top nuclear negotiator says talks on his country's nuclear program will be a long process, dashing hopes for a breakthrough in the standoff.

Ali Larijani spoke after his latest talks in Brussels with European Union foreign policy chief Javier Solana. They met to discuss the incentives that the world's major powers are offering for Iran to suspend sensitive nuclear work. 

Larijani urged patience in the dispute, apparently rebuffing international pressure to formally respond to the offer.

Solana says he will discuss Tuesday's meeting with the foreign ministers of the countries behind the offer - the United States, Russia, China, Britain, France and Germany.  Those officials meet Wednesday in Paris to discuss whether to continue pursuing talks with Iran or seek punitive action by the United Nations Security Council.

Iranian President Mahmoud Ahmedinejad says his country will not back down from its right to produce nuclear fuel.

In Washington, U.S. Secretary of State Condoleezza Rice and British Foreign Secretary Margaret Beckett said Monday it is time for Iran to reply to the incentives.

The United States and many of its allies believe Iran is planning to build nuclear weapons.  Iran insists its nuclear program is for peaceful purposes.

Some information for this report was provided by AFP and AP.