US under secretary of state Nicholas Burns made the comments after talks with EU foreign policy chief Javier Solana and members of the so-called EU-3 -- France, Britain and Germany -- due to hold talks with Iran in Geneva Wednesday.

"The US supports the EU-3's negotiating efforts to end Iran's nuclear weapons ambitions. Iran must not be allowed to acquire a nuclear weapons capability," he said.

"Iran has an obligation to demonstrate to the world it is not doing so," he added.

He said that Tehran -- which Washington has long suspected of seeking to develop nuclear bombs -- must abide by an accord struck with the Europeans in Paris last November, under which it vowed to freeze key nuclear activities.

"We call on Iran to adhere to the Paris agreement, maintain its suspension of nuclear-related activities, and negotiate in good faith the cessation and dismantling of all sensitive nuclear fuel activities," he said.

The EU-3 and Iran held official-level talks in Brussels on Tuesday to prepare for the Geneva talks. Afterwards an Iranian negotiator said there was only a "50-50" chance of success.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.