Iran nuclear talks near crunch time

US Secretary of State John Kerry (pictured above right) warned of difficulties in talks about a nuclear deal with Iran as Monday's deadline for an agreement approaches.

"We're working hard," Kerry said in Vienna, "and we hope we're making careful progress, but we have big gaps, we still have some serious gaps, which we're working to close."

Kerry, who remained in Vienna after postponing a trip to Paris on Friday, met Iranian Foreign Minister Mohammad Javad Zarif (above left) on Saturday afternoon. The meeting was the pair's fourth in three days.

Six world powers - the United States, Russia, China, Britain, France and Germany (known as the P5+1 group) - have been locked in talks with Iran since February. They hope to turn an interim accord reached a year ago into a lasting agreement by November 24.

Any deal would be aimed at easing fears that Tehran might develop nuclear weapons under the guise of its civilian activities.

Stumbling blocks

While the P5+1 wants Iran to reduce its program of enrichment - a process that renders uranium suitable for peaceful uses but also to make a nuclear weapon - Tehran wants to increase it. Iranian leaders are also frustrated by what they see as a lack of pace in any proposed lifting of sanctions against Iran.

German Foreign Minister Frank-Walter Steinmeier on Saturday said Tehran and the six powers had "never been closer" to an agreement since they started negotiating more than six years ago.

However, he echoed Kerry in saying both sides are "still far apart" on certain questions. Steinmeier said the talks had reached "a moment of truth." But, he said, success or failure was "still completely open at this point."

One Iranian official appeared to agree, but appeared to place the onus on the international negotiators to make concessions to Tehran. "The gap remains big... There now needs to be a political decision," the unnamed source told the news agency AFP.

rc/av (AFP, AP, dpa, Reuters)