WASHINGTON — U.S. Supreme Court Justice Ketanji Brown Jackson said on Thursday attacks by Republican President Donald Trump and his allies on judges were “not random” and seemed “designed to intimidate the judiciary.”

Chief Justice John Roberts rebuked Trump in March for urging the impeachment of a federal judge, laying bare tensions between the country’s executive and the judiciary as Trump’s sweeping assertions of power encounter judicial obstacles.

“The attacks are not random. They seem designed to intimidate those of us who serve in this critical capacity,” Jackson said at a judges’ conference in Puerto Rico.

Federal judges have said the Trump administration has failed to comply with court orders regarding foreign aid, federal spending and the firing of government workers. The administration disputes it has defied judges but has been critical of orders and judges that have blocked its actions.

“The threats and harassment are attacks on our democracy, on our system of government. And they ultimately risk undermining our Constitution and the rule of law,” Jackson said.

Jackson, an appointee of former Democratic President Joe Biden, did not mention Trump by name but spoke about “the elephant in the room.”

Her comments were cited in media reports from Politico and the New York Times, with Politico noting that her comments got a standing ovation.

The combative atmosphere under the Trump administration has raised concerns among some legal experts of a potential constitutional crisis.

The Supreme Court has a 6-3 conservative majority.