U.S. officials will return to the negotiating table with Iran Thursday, Aug 7, for the first time since nuclear talks were extended beyond their original deadline, the State Department announced, according to The Hill.

The meeting marks the resumption of negotiations after diplomats left Geneva last month after failing to broker a deal before the original July 20 deadline.

Deputy Secretary of State William Burns, Under Secretary for Political Affairs Wendy Sherman, and National Security Advisor to the Vice President Jake Sullivan will meet with Iranian officials in Switzerland.

Other world powers, including Britain, France, Germany, Russia and China, are not expected to participate in the meeting.

Under the agreement struck to extend the deadline, the U.S. agreed to suspend certain economic sanctions over the next four months, freeing $2.8 billion in Tehran’s frozen assets. In exchange, Iran agreed to dilute the remainder of its 20 percent enriched uranium into fuel form, making it more difficult to weaponize. Tehran has also agreed to maintain the freeze of its nuclear weapons program.

Last month, President Obama touted "real progress" in the talks and said he saw “a credible way forward” in the negotiations.

The resumption of the talks is certain to draw criticism from some corners of Capitol Hill, where a bipartisan group of lawmakers has cautioned against continuing the negotiations.

Sens. Robert Menendez (D-N.J.) and Lindsey Graham (R-S.C.) are reportedly circulating a letter asking their fellow senators to support a plan that would require Iran to agree to at least two decades of inspections before Congress agrees to ease financial sanctions.

Earlier this year, Menendez and Sen. Mark Kirk (R-Ill.) presented legislation that would cut Iranian oil exports and restrict the administration's ability to ease sanctions. That effort was ultimately blocked by Democratic leadership.

But an administration official has expressed confidence that the additional concessions offered by Tehran offered "added value" that will make the extension more attractive to lawmakers. "What we are able to say to Congress today is there are very specific areas where we have made concrete progress," said the official.