The U.S. State Department announced Undersecretary of State for Political Affairs Wendy Sherman left Sunday for Geneva, Switzerland, to take part in multilateral nuclear negotiations with Iran.
Iranian President Hassan Rouhani spoke by phone with U.S. President Barack Obama last month. Obama has said he'd respect Iran's right to nuclear research so long as he had assurances from Iran it wouldn't weaponize the program.
U.S. Rep. Ed Royce, R-Calif., chairman of the House Foreign Affairs Committee, said it would be difficult to negotiate with Iran over is uranium enrichment program. Iranian officials said enrichment was a "red line."
"It is clear that U.S. negotiators face an uphill battle," Royce said in a Monday letter to Obama. "As such, it is critical that we maximize our negotiating leverage through the immediate implementation of additional economic sanctions."
Tehran last week said it was ready to provide assurances that its nuclear program is for peaceful purposes -- but only if Western leaders lift sanctions on Iran.