Utah Sen. Mitt Romney is criticizing President Donald Trump for calling on China to investigate former Vice President Joe Biden.

Trump on Thursday called for China to investigate Biden, his son Hunter and his business deals in the country. A similar request to Ukraine has triggered an impeachment inquiry in the Democratic-controlled House.

Republicans were relatively muted in their reaction. But Friday, Romney tweeted: “By all appearances, the President’s brazen and unprecedented appeal to China and to Ukraine to investigate Joe Biden is wrong and appalling.”

Romney last week had been the rare Republican to warn that the allegations regarding Trump’s dealings with Ukraine were “deeply troubling.”