"If we are to speak about some sort of exchange, the question has not been presented in such a way, because it is not productive," he said when asked about a letter US President Barack Obama wrote to him regarding the two issues.

"Our American partners are ready to discuss this problem," added Medvedev at a joint news conference with Spanish Prime Minister Jose Luis Rodriguez Zapatero. "This is already good."

Earlier Tuesday the New York Times reported that Obama suggested in a secret letter sent to Medvedev three weeks ago that Washington would back off deployment of the missile defense shield if Moscow would help stop Iran from developing long-range missiles.

Confirming that Obama sent a letter to Medvedev, a senior US official told AFP on condition of anonymity that the missive covered "a broad range of topics including missile defense and how it relates to the Iranian threat."

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.