Obama also said that Iran's leaders had chosen to isolate themselves, despite his offer last year of a "new beginning" in relations between Washington and Tehran.

He promised US efforts to "ensure that Iranians can have access to the software and Internet technology that will enable them to communicate with each other, and with the world, without fear of censorship."

In excerpts of the address released by the White House, Obama said his offer of dialogue with Iran still stands, and repeated his line that Tehran should be held accountable after failing to meet its nuclear obligations.

"Over the course of the last year, it is the Iranian government that has chosen to isolate itself, and to choose a self-defeating focus on the past over a commitment to build a better future,"

The full address was due to be released later on Saturday, officials said.

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.