Former US Defense Secretary Robert Gates warned of imposing new sanctions against Iran, saying that such a move would be “mistake and a deal-killer”.

Former US Defense Secretary Robert Gates warned of imposing new sanctions against Iran, saying that such a move would be “mistake and a deal-killer”.

"To vote additional sanctions today would be I think a deal-killer," said Gates on Thursday.

"I think that the president's opposition to a bill that would impose additional sanctions now is absolutely right," added Gates, who served as defense secretary under President Barack Obama and his predecessor George W. Bush.

The former Pentagon chief was referring to a draft bill, introduced by Chairman of the US Senate’s Foreign Affairs Committee Robert Menendez (D-NJ) and Senator Mark Kirk (R-Ill.) on December 18, 2013, that would impose further sanctions on Iran, targeting the country’s energy, shipping and mining sectors.

The bill that enjoys the support of 59 senators, would violate the terms of an agreement reached on November 24, 2013, between Iran and the five permanent members of the United Nations Security Council - Britain, China, France, Russia, the United States – plus Germany in Geneva, Switzerland. The two sides have also agreed on January 20 as the date to start implementing the deal.

The draft bill and the subsequent efforts by Menendez and Kirk to rally support for it have faced strong opposition from the White House. Obama has said he would veto the bill if it were to pass in the Congress.

On Monday, Obama once again warned Congress against imposing new economic sanctions on Iran.