Sen. Bob Menendez, D-N.J., on Wednesday demanded Secretary of State Mike Pompeo recuse himself of all Ukrainian issues "to prevent further erosion of the integrity of U.S. foreign policy" in light of his role in the investigation surrounding President Donald Trump's telephone call.

"There are serious questions concerning your role in the leveraging of U.S. security assistance, taxpayer dollars, to advance President Trump's personal and political agenda," Menendez, ranking Democrat on the Senate Foreign Relations Committee, said in a letter to Pompeo.

"The American people need to have confidence that the nation's chief diplomat is making decisions based on the national interest, not to advance a partisan political agenda.

"Recusal is the only option at this point to prevent further erosion of the integrity of U.S. foreign policy," Menendez said.

Pompeo acknowledged Wednesday he was on the July 25 call between Trump and Ukrainian President Volodymyr Zelenskiy that is the focus of the House impeachment probe, telling reporters in Rome: "I was on the phone call."

He explained, as America's top diplomat, he was well-versed in U.S. policy toward Ukraine — and Pompeo remained defiant against the Democrats, attacking them for "bullying and intimidation."

Pompeo has tried to delay five current and former State Department officials from providing documents and testimony, but Democrats have scheduled closed-door depositions for Thursday for former special envoy to Ukraine Kurt Volker and next week for ousted U.S. Ambassador Marie Yovanovitch.