The White House wants Congress to stop interfering in the negotiations with Iran about its nuclear capabilities.
White House Chief of Staff Dennis McDonough warned Congress in a letter sent late Saturday that pending legislation requiring congressional approval for any deal reached with Iran about its nuclear capabilities could have a "profoundly negative impact" on the negotiations.
White House officials have said President Barack Obama would veto the proposed legislation.
U.S. Secretary of State John Kerry travels to Switzerland Sunday for another round of talks with his Iranian counterpart, Mohammad Jawad Zarif, in an attempt to reach an interim deal with Iran on its nuclear power program by a March 31 deadline.