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