Brussels - US President Barack Obama's offer of direct talks with Iran is a "very good" one and deserves an "intelligent" response, the man who heads international negotiations over Iran's controversial nuclear programme said Friday.

Obama's offer of a new diplomatic start with Tehran is a "very constructive message" and a "very good offer," and "I hope very much that Iran will react intelligently," the EU's top diplomat, Javier Solana, told journalists on the fringes of an EU summit in Brussels.

Solana, a former nuclear physicist, is tasked with negotiating with Tehran on behalf of the United Nations Security Council's permanent members and Germany.

That task has long been complicated by the refusal of the US to talk directly with Iran.

So while the world's great powers will "maintain that format" and "will have to tackle the nuclear issue," Solana said that he was "very pleased" by Obama's desire to "reach out to Iran."

"I hope very much Iran will pay good attention to what has been said by President Obama. I hope this will open a new chapter in the relations with Tehran," he said.

Obama has been particularly keen to engage with Iran over its nuclear programme and in its role as a neighbour of Afghanistan, where US troops are facing a bitter struggle with the Taliban.

He has already proposed convening a so-called "big tent" summit on Afghanistan for March 31, which would include major regional players such as Iran and Pakistan. (dpa)