The White House has issued a new warning to the US Senate to stay out of negotiations with Iran over its nuclear program. 

Chief of staff Denis McDonough tells Senate Foreign Relations Committee Chairman Bob Corker in a letter yesterday that legislation the Republican is sponsoring would potentially prevent any agreement from succeeding by asserting that Congress must vote to approve any deal.

McDonough also criticizes a provision that would undo President Barack Obama’s authority to lift existing sanctions on Iran.

McDonough reiterates the White House position that congressional action before a deal is reached would be harmful to the talks, which are to resume Sunday in Switzerland.

The US and other world powers involved in the negotiations face a March 31 deadline to reach a framework deal with Iran.