With their milestone nuclear deal now in effect, Iran and six world powers are focusing on coordinating who needs to do what first for the agreement to be fully implemented.

The agreement was reached July 14 but was officially adopted Sunday. The accord foresees deep cuts in Iranian nuclear programs in exchange for sanctions relief. Senior officials from all seven countries were meeting Monday in Vienna on sequencing.

The United States expects Iran will take months to live up to its end of the deal. U.S. officials insist that no relief from the penalties will occur until the U.N.'s International Atomic Energy Agency has verified Iran's compliance with the terms of the agreement.

They say Iran's work will almost certainly take more than the two months Tehran has projected.