The White House on Friday warned that an ongoing government shutdown could weaken enforcement of U.S. sanctions against Iran, adding a foreign-policy wrinkle to the administration's push to end the impasse in Washington.

While Obama spokesman Jay Carney never said outright that sanctions had been imperiled, he argued the furloughs of all but 11 employees at the Treasury Department's Office of Foreign Assets Control could have dire consequences. That division of Treasury is responsible for levying the sanctions against Iran, Syria and other nations the U.S. is looking to pressure with economic punishment.

“It illustrates the consequences that the Republican shutdown continues to have on the government's missions and workers across the country," Carney told reporters.

The White House fears that lax enforcement of sanctions could weaken pressure on Iran ahead of talks where the U.S. hopes the Rouhani regime will make concessions on Tehran's nuclear program.

Republicans though say that the Obama administration is already weakening international support for sanctions by pursuing diplomatic talks with Iran. Conservative lawmakers warn that Tehran is stalling for time and is developing nuclear arms.

House Foreign Affairs Committee Chairman Ed Royce, R-Calif., criticized the staffing decisions.

"Needless to say, these recent staffing decisions leave me puzzled," Royce wrote to Treasury Secretary Jack Lew. "I respectfully ask that you reconsider these ill-advised staffing decisions that undermine support for vigorous Iran sanctions and other critical national security efforts."

Obama recently had a phone conversation with Iranian President Hassan Rouhani, the first such communication between the leaders of the two countries in more than three decades.