Washington (CNN) Senators furious about the killing of Jamal Khashoggi are working on a bipartisan effort to exert more pressure on the White House as Secretary of State Mike Pompeo insisted Monday the administration is not "covering up for a murder."

Sen. Bob Menendez, the ranking Democrat on the Senate Foreign Relations Committee, told CNN Monday that he is working with South Carolina Republican Sen. Lindsey Graham to "hold the administration's feet to the fire" on Saudi Arabia and its admitted, pre-meditated murder of the Washington Post journalist.

Graham said he and Menendez are "going to take appropriate action" to put a bill on the President's desk, and called the murder of Khashoggi "barbaric beyond acceptance."

"We believe the Crown Prince -- MBS -- had a hand in this. It couldn't have happened without his knowledge and approvals and we're going to take appropriate action," he added.

Menendez and Graham spoke after the administration's decision Friday not to properly respond to a congressional deadline requiring the President to determine whether Saudi Crown Prince Mohammed bin Salman is responsible for the murder and if sanctions will be levied as a result.

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