COLUMBIA, S.C. - Gov. Nikki Haley has signed into law a bill that prohibits South Carolina from investing funds or contracting with international companies that have invested at least $20 million in Iran's energy sectors.

According to the watchdog group United Against Nuclear Iran, South Carolina joins 29 other states that already have divestment laws against Iran since President Barack Obama signed legislation in 2010 allowing states to enact their own individual sanctions. But it said the measure signed Monday would be the first by a state to implement sanctions since an interim deal was struck in January between Iran and six world powers, including the U.S., which lifted some sanctions that are crippling Iran's economy.

In exchange, Iran agreed to inspections of its nuclear facilities and froze or dismantled parts of its nuclear energy program that allowed it the capability to produce nuclear weapons. Negotiators meeting in Vienna, Austria are under a self-declared informal deadline of July 20 to reach a comprehensive deal.

Blaise Misztal, Director of Foreign Policy at the Bipartisan Policy Center, said the timing of South Carolina's action to impose sanctions is curious but it does not violate the interim deal, which only applies to nationwide US and European Union sanctions. But he said it does go against the spirit of the agreement and could be used by either side in the talks though it has no real financial impact.

"Iran could claim that it's outraged by this and demand to be taken more seriously but the world powers could also say, 'Look this is going to continue happening unless you give up your nuclear program,'" Misztal said.

Paul Carroll with Ploughshares Fund, the largest public foundation that works to avert nuclear risk, agreed. He said sanctions have already brought Iran to the negotiation table.

"They are feeling the pain and they have understood that the way to reduce that pain is to move toward a more transparent and less weapons-prone nuclear program," said Carroll.

A U.S. state imposing sanctions this late smacks of political positioning when there's still work to be done in the talks, Carroll said.

South Carolina Republican and U.S. Sen. Lindsey Graham, a member of the Senate Armed Services Committee, said the bill sends a message to Iran that it's not welcome in the state as long as it tries to pursue nuclear weapons and threaten the U.S. and Israel.

Graham criticizes Obama for the easement of sanctions and said the agreement being sought would still leave Iran with the ability to pursue its program.

The state Senate vote on the measure May 28 coincided with a visit to the State House by Israeli Ambassador Ron Dermer. The same day Dermer also attended two events hosted by Christians United for Israel with Graham.

Israel isn't part of the talks but has been watching closely for any signs Tehran could be using them as a cover while trying to reach the ability to make a nuclear weapon - something the Jewish state has vowed to prevent by any means, including force.

Co-sponsor Rep. Bakari Sellers, D-Denmark, said more sanctions would give negotiators greater leverage in pressing Iran to give up further concessions in pursuit of a final agreement.

"What we are trying to do is to preserve one of the only democracies that we have in the Middle East and to make sure that we have a safe and secure Israel," said Sellers. The bill's other main sponsor is Rep. Alan Clemmons, R-Myrtle Beach.