Washington(CNN) Energy Secretary Rick Perry, who has met on at least three occasions with Ukrainian President Volodymyr Zelensky, on Wednesday pledged to work with lawmakers looking into a whistleblower's allegations about President Donald Trump's communications with Zelensky.
"I'll just briefly say we're going to work with Congress and answer all their questions," Perry said at a department event on artificial intelligence and energy.
Perry has met with Zelensky at least three times while in office, including when replaced Vice President Mike Pence in leading a US delegation to Zelensky's inauguration last spring.
On Tuesday, Sen. Bob Menendez of New Jersey, the top Democrat on the Foreign Relations committee, sent a letter questioning Perry about that trip as well as his second meeting with Zelensky, a June 2019 dinner.
Energy Department spokeswoman Shaylyn Hynes told CNN, "Regardless of subject, the Department is always willing to work with Congress in response to requests that follow proper procedures."
The whistleblower complaint alleges that on a July phone call, Trump asked Zelensky to investigate 2020 Democratic presidential hopeful Joe Biden. The complaint also said the White House attempted to cover up the matter.
Trump, the whistleblower says, "instructed Vice President Pence to cancel his planned travel" because he wanted to see "how Zelenskyy 'chose to act' in office."
Asked on Wednesday why he may have been asked to replace Pence, Perry said, "Oh I think it's because I'm just such a darned good Cabinet member, and very capable, and probably pretty knowledgeable about the energy industry."
Some in the audience could be heard laughing as Perry spoke.
A source who accompanied Perry on that trip told CNN they never heard Biden come up in discussions, or as part of the mission for the trip. The source said Perry regularly travels at the behest of the White House.
Perry is close with Trump, often receiving calls from the President on his cell phone, but isn't at the White House as much as Secretary of State Mike Pompeo or Treasury Secretary Steven Mnuchin, explained the source, adding that's one of the reasons Perry has lasted so this long in the administration, where top officials are constantly being fired.
A summary of Perry's meeting with Zelensky on that trip describes their conversations about energy pipelines and says Perry promised -- "on behalf of President Trump and his Administration" -- to "continue to support our friend and ally, Ukraine, against Russia's aggression."
The first two meetings between Perry and Zelensky took place prior to the Trump phone call, according to the Menendez letter and readouts from the Energy Department.
The third meeting between Perry and Zelensky occurred in late August, according to an Energy Department statement at the time. It said the two men, were joined by Pence and John Bolton, who was later ousted as national security adviser.
"President Zelenskyy articulated his administration's commitment to defeating corruption and pledged to launch much anticipated reforms," the Energy Department's statement said.
Menendez also asked Perry if he has any knowledge of the National Security Council's secure system for classified records. The whistleblower said the transcript of the Trump-Zelensky call was inappropriately stored in this system rather than the typical system for presidential calls.
Perry also met in Ukraine with Zelensky's predecessor in August 2017 and visited the country on a Baltic region tour in November 2018.