WASHINGTON • Setting a defiant tone, the Trump administration resisted Congress’ access to impeachment witnesses Tuesday, even as House Democrats warned such efforts themselves could amount to an impeachable offense.

Secretary of State Mike Pompeo tried to delay five current and former officials from providing documents and testimony in the impeachment inquiry that could lead to charges against President Donald Trump.

But Democrats were able to set closed-door depositions for Thursday for former special envoy to Ukraine Kurt Volker and next week for ousted U.S. Ambassador Marie Yovanovitch.

The escalating exchange of accusations and warnings signaled yet another stiffening in the confrontation between the executive and legislative branches amid the Democrats’ launching of the impeachment inquiry late last week.

That followed a national security whistleblower’s disclosure of Trump’s July phone call seeking help from the new Ukrainian president in investigating Democratic political rival Joe Biden and Biden’s son Hunter.

Pompeo said the Democrats were trying to “intimidate” and “bully” the career officials into appearing and claimed it would be “not feasible” as demanded. House investigators countered that it would be illegal for the secretary to try to protect Trump by preventing the officials from talking to Congress.

Some Trump supporters cheered Pompeo’s muscular response to the Democrats. But it also complicated the secretary’s situation, coming the day after it was disclosed that he had listened in during Trump’s July phone call with Ukrainian leader Volodymyr Zelenskiy that helped trigger the impeachment inquiry.

“Any effort to intimidate witnesses or prevent them from talking with Congress — including State Department employees — is illegal and will constitute evidence of obstruction of the impeachment inquiry,” said three House chairmen, Adam Schiff of the intelligence committee, Eliot Engel of Foreign Affairs, and Elijah Cummings of Oversight.

They said that if he was on Trump’s call, “Secretary Pompeo is now a fact witness in the House impeachment inquiry.” And they warned, “He should immediately cease intimidating Department witnesses in order to protect himself and the President.”

The committees are seeking voluntary testimony from the current and former officials as the House digs into State Department actions and Trump’s other calls with foreign leaders that have been shielded from scrutiny.

In halting any appearances by State officials, and demanding that executive branch lawyers accompany them, Pompeo is underscoring Attorney General William Barr’s expansive view of White House authority and setting a tone for conflicts to come.

“I will use all means at my disposal to prevent and expose any attempts to intimidate the dedicated professionals,” Pompeo wrote.

Secretary of State Mike Pompeo listens as President Donald Trump speaks Monday during an Armed Forces welcome ceremony for the new chairman of the Joint Chiefs of Staff Gen. Mark Milley.

the associated press