U.S. Secretary of State John Kerry says it is "unclear" whether a framework agreement on Iran's nuclear program can be reached by the end of the month.
Kerry made the comments on March 14 at an investment conference in Egypt's Red Sea resort town of Sharm El-Sheikh. The remarks come just ahead of a fresh round of talks with Iran in Switzerland set to begin on March 15.
Kerry said, "We continue to be focused on reaching the right deal, a deal which would protect the world, including the United States and our closest allies and partners, from a threat that a nuclear armed Iran could pose."
But Kerry added, "We still don't know whether or not we will get there" and said that "important gaps" still remain in the bargaining process.
"Nothing in our deliberations is decided until everything is decided," Kerry said.
Kerry also mentioned the March 9 letter authored by 47 Republican senators that was sent to Iran's Supreme Leader Ayatollah Khamenei warning that the deal currently being negotiated could be canceled after the next U.S. presidential elections when a new president takes office in early 2017.
Kerry called the letter "direct interference in the negotiations of the executive department" and said it would inevitably "raise questions in the minds of folks with whom we are negotiating."
Khamenei already commented on the letter on March 12, saying U.S. officials habitually become "harsher, tougher, and coarser" when progress is being made in negotiations and adding the United States is known for its "deceit and backstabbing."
The United States and five other powers have set a deadline of the end of March for a framework deal on Iran's nuclear program, which many countries suspect may be a cover for making weapons.
Iran claims its nuclear program is peaceful.