White House press secretary Jay Carney on Thursday said the administration is “not expecting any breakthroughs” in initial nuclear talks between Iran and the United States.

Carney said the meetings would allow for “testing the seriousness of the Iranians,” though.

His comments come as Iran’s foreign minister is set to meet with Secretary of State John Kerry and other representatives from the P5+1 group that is seeking to reach a diplomatic solution over Iran’s nuclear energy program.

The meeting comes after a number of diplomatic overtures from the government of newly-elected Iranian President Hassan Rouhani. Rouhani, seen as a moderate by Iran watchers, has called for a “constructive” dialogue with the U.S. and vowed not to build nuclear weapons.

President Obama in an address to the United Nations on Tuesday said he was directing Kerry to pursue diplomacy with Iran. He also vowed to oppose efforts by Tehran to develop nuclear weapons capability.

But lawmakers have cautioned the administration against rushing into a detente with Iran, arguing that Tehran may be stalling for time to develop nuclear weapons.

Carney said he “wouldn’t put a timeline on” the diplomatic process. “These are obviously complicated issues,” he added.

“We hope and expect to see progress if Iran is serious and if the new government is serious,” said Carney.