U.S. Secretary of State Hillary Clinton says if major powers resume talks with Iran about its nuclear program, the discussion must<br/> <br />be a sustained effort that can produce results.<br/> <br />(SOUNDBITE) (English) U.S. SECRETARY OF STATE HILLARY CLINTON SAYING:<br/> <br />"This response from the Iranian government is one we have been waiting for and, if we do proceed, it will have to be a<br/> <br />sustained effort that can produce results,"<br/> <br />Clinton spoke at a news conference with European Union foreign policy chief Catherine Ashton, who received a letter from Iran earlier in the week proposing reopening talks on Iran's nuclear program.<br/> <br />(SOUNDBITE) (English) EUROPEAN UNION FOREIGN POLICY CHIEF CATHERINE ASHTON:<br/> <br />"I think it is good to see that the letter has arrived and there is the potential, the possibility, that Iran is ready to start talks. I am cautious and optimistic at the same time."<br/> <br />The meeting comes days after Iran touted advances in its nuclear technology -- with Iranian State TV airing video of President Mahmoud Ahmadinejad loading nuclear fuel rods into a reactor.<br/> <br />The West accuses Tehran of using its nuclear program to pursue weapons capability and has slapped sanctions on the country's oil industry which have hit the wider economy hard.<br/> <br />Iran rejects the charge and insists its program is purely for peaceful nuclear power generation purposes.<br/> <br />Deborah Lutterbeck, Reuters.