“The president asked a foreign power to help him win an election. Again,” she dryly tweeted — clearly referencing Russia’s role in the 2016 presidential election.

Hillary Clinton landed an icy dig on Friday amid the controversy over President Donald Trump ’s alleged strong-arming of the Ukrainian president to investigate political rival Joe Biden and his son.

The president asked a foreign power to help him win an election. Again. https://t.co/EjkE84oCCF

Clinton attached a clip of Trump attorney Rudy Giuliani’s meltdown in a CNN interview Thursday when he said that “of course” he called on Ukrainian officials recently to investigate Biden, after initially denying it.

Clinton’s attack was one of several in the wake of a Wall Street Journal article published Friday which reported that Trump pressed Ukrainian President Volodymyr Zelensky “about eight times” in a July phone call to work with Giuliani on an investigation of the former vice president’s actions as well as those of his son, Hunter.

Giuliani has claimed that Biden worked when he was vice president to shield a Ukrainian energy company linked to Hunter from a corruption probe. A Ukrainian official said earlier this year there was no evidence of any wrongdoing by either Biden.

Trump’s request for a Ukrainian investigation into the Bidens is part of a secret complaint filed against the president by a whistleblower in the intelligence community, The New York Times reported Friday.

Trump hasn’t denied pressing Zelensky to investigate the Bidens. He has described the call with Zelensky as “beautiful,” and said it “doesn’t matter what I discussed.”

The possibility of a president leveraging the power of the U.S. government on a foreign country to probe a political rival to help his reelection has begun to trigger calls for impeachment.

Former Texas Rep. Beto O’Rourke, former Secretary of Housing and Urban Development Julian Castro, New Jersey Sen. Cory Booker and Massachusetts Sen. Elizabeth Warren appeared to be the first of the Democratic presidential contenders to call for Trump’s impeachment over the matter on Friday. Like Clinton, both O’Rourke and Warren referred to Russian interference in the 2016 election.