Iran’s Foreign Minister is supposed to meet his American counterpart today to continue discussion over Iran’s nuclear program, as the deadline for agreement approaches. The U.S. and Iranian foreign ministers will meet on Saturday, as major differences persist over an agreement under which Iran would curb its nuclear program in exchange for sanctions relief. U.S. Secretary of State John Kerry and Iranian Foreign Minister Mohammad Javad Zarif will sit down in the Austrian capital ahead of Tuesday's self-imposed deadline, which many officials expect to slip. Significant gaps remain, notably over the sequencing of economic sanctions relief for Iran and the nature of monitoring mechanisms to ensure Tehran does not cheat on any agreement. "The next few days will be extremely difficult," a senior Western diplomat said on condition of anonymity, adding that the talks may slide at least two or three days past the deadline. Senior Iranian negotiator Abbas Araqchi told Iranian reporters that the current negotiations were a "slow and difficult process." In addition to Iran and the United States, the talks include Britain, China, France, Germany and Russia. Foreign ministers from all the nations are expected in Vienna in the coming days to "check in" on the progress of negotiations.