President Trump said on Thursday that it is “a great honor” to have Rudy Giuliani on his side and called him “one of the great crime fighters in the history of our country.” Trump also claimed that he does not know “anything” about a letter that Giuliani allegedly wrote that says Trump was aware of his activities in Ukraine but added that if his personal attorney did write a letter, “it wouldn’t be a big deal.” The president’s comments came on the same day that Ukraine’s government announced a criminal investigation into alleged surveillance of then-U.S. Ambassador to Ukraine Marie Yovanovitch in Kyiv amid a push to oust her from her post. Texts made public between Giuliani’s associate Lev Parnas and Robert Hyde, a Trump donor and Connecticut congressional candidate, indicated that Yovanovitch’s movements were illegally being monitored. Trump also said Giuliani is “the greatest mayor in the history of New York” and that he did a “phenomenal job over a long period of time in fighting crime.”