U.S. Secretary of State Marco Rubio got short with reporters on Thursday when asked to address a new report alleging that U.S. Ambassador to Greece Kimberly Guilfoyle engaged in potentially illegal conduct prior to assuming her post.

Rubio told reporters that he “understood the game” they were trying to play but would not debate claims published in a Wall Street Journal report, which stated Guilfoyle requested that a donor and supporter of U.S. President Donald Trump cover a $100,000 credit card balance shortly before her confirmation hearing, allegedly pledging access to administration officials in return.

His remarks came before departing Greece, where he had delivered a speech urging European nations to return to what he characterized as their civilizational roots.

Rubio acknowledged being aware of The Wall Street Journal’s story, published late Wednesday, but maintained he had no knowledge of its accuracy and would not discuss it further.

“You guys walk around thinking that because some source told you something and you reported it, it’s the gospel. It’s not the gospel. It’s not the gospel for me. That’s not the way we do things,” he stated at the foot of his aircraft while Guilfoyle, present to see him off, looked on.

Speaking at a joint press conference alongside the Greek foreign minister on Wednesday, Rubio reiterated that he would not comment on the allegations while abroad, adding, “Suffice it to say our embassy here is doing a great job. Our ambassador has been a strong ambassador here.”

The senior Democrats on the House Foreign Affairs and Senate Foreign Relations committees have demanded an investigation into Guilfoyle, though Rubio refused to state whether he was willing to initiate one.

Congressional Democrats were already scrutinizing claims detailed last month by the Wall Street Journal alleging improper behavior by Guilfoyle during her tenure as top U.S. envoy to Greece.

According to the Journal, Guilfoyle informed guests at a reception that the U.S. could destabilize the Greek government if it desired, championed the commercial interests of a specific Greek construction and energy firm, and permitted its lobbyist to attend confidential diplomatic sessions.

Guilfoyle, a former Fox News Channel host and California prosecutor once engaged to Trump’s son Donald Jr., has rejected all allegations of misconduct, and Rubio has previously offered her his backing.