Tehran
TehranAFP photo

A top U.S. official said on Thursday that limited sanctions relief for Iran is possible if it takes confidence-building steps to allay concerns about its nuclear program, but that fundamental measures must remain in place until all issues have been dealt with.

According to a report in Voice of America (VOA), State Department Under Secretary for Political Affairs Wendy Sherman told a Senate panel that any diplomatic engagement with Iran will be accompanied by the "vigorous enforcement" of sanctions already in place.

She described the measures — imposed following Iran's refusal to halt uranium enrichment — as "the toughest sanctions the world has ever seen" and asserted they have forced Tehran to the negotiating table.

"Twenty-three economies have united in significantly reducing or eliminating purchases of Iranian crude oil. Over the past 24 months, Iran's rial has depreciated by approximately 60 percent as Iran's access to the international financial sector has been largely severed," said Sherman, according to VOA.

But while the tough measures have worked so far, the United States government shutdown has forced the Treasury Department to furlough most employees enforcing sanctions on Iran, just as new negotiations are set to begin.

U.S. officials said the department’s Office of Foreign Assets Control, responsible for enforcing economic and trade sanctions against Iran and Syria, is being hindered because it has been pared down to a “skeleton crew.”

Earlier Thursday, Secretary of State John Kerry expressed cautious hope about engaging with Iran over its nuclear program, but said Iran must take concrete steps to prove its sincerity.

Speaking Thursday in Tokyo, Kerry said nothing will be taken at face value.

"I assure (Prime Minister Binyamin) Netanyahu and the people of Israel that nothing that we do is going to be based on trust," Kerry said.

Rather, Kerry explained, "it is going to be based on a series of steps to guarantee to all of us that we have certainty on what's happening."

Fears about Iran's nuclear program remain a key issue, with Western nations and Israel saying Iran is working to develop nuclear weapons. Iran has long said its program is peaceful.

U.S. President Barack Obama said last week in a phone call with Iran’s new president, Hassan Rouhani, that he believes a comprehensive solution can be reached over Iran's nuclear program, and that the two sides are moving forward.

At the same time, Obama assured Netanyahu during a meeting this week that Iran must prove its sincerity through actions before getting any relief from the sanctions.