Behind closed doors in Vienna, negotiations over Iran's nuclear program are intensifying ahead of a November 24 deadline to reach a deal.<br /> <br />At stake is the resolution of a 12-year standoff between Iran and the West over Tehran's nuclear ambitions.<br /> <br />At a news conference with German Foreign Minister Frank-Walter Steinmeier, U.S. Secretary of State John Kerry is cautious.<br /> <br />(SOUNDBITE) (English) U.S. SECRETARY OF STATE JOHN KERRY SHAKING HANDS WITH GERMAN FOREIGN MINISTER FRANK WALTER STEINMEIER, SAYING:<br /> <br />"We hope we're making careful progress, but we have big gaps, we still have some serious gaps, which we're working to close."<br /> <br />Western officials have accused Iran of seeking to develop a nuclear bomb.<br /> <br />Iran says its program is purely peaceful.<br /> <br />One key issue is uranium enrichment, which has both civilian and military use.<br /> <br />Another issue is sanctions. Iran wants sanctions to be ended quickly while the West wants a gradual approach.<br /> <br />As the talks
