Trump ​campaign ​adviser Roger Stone ignored a subpoena to testify in a Manhattan defamation case Wednesday because he was in Washington​,​ D.C.​,​ responding to a demand by ​the ​Senate Intelligence Committee to produce documents​ related to the probe of contacts with Russia authorities​, his attorney said in court.

Stone is under investigation by the F.B.I.​ and Congress ​for his potential involvement in Russia’s attempt to interfere with the ​2016 ​U.S. presidential election. He has denied any role in the meddling.

Stone’s lawyer, Benjamin Burge, said his client has not yet been called to appear before the congressional committee.

The committee gave Stone, a longtime champion of Donald Trump’s presidential ambitions and a former aide to Richard Nixon, a notice instructing him to preserve documents, Burge said.

He did not provide any more details about the notice, but said there was no deadline. Stone first received the notice in mid-March.

Judge Richard Braun said ​regardless of teh Russia probe ​Stone must appear in Manhattan Supreme Court to answer questions.

Stone is facing a multi-million dollar civil case filed by a failed 2010 candidate for the governor of New York. That candidate, Libertarian Warren Redlich, says Stone was behind a defamatory flier sent to over 150,000 voters that called him a child molester.

Redlich’s opponent in the 2010 race, Carl Paladino, and his former campaign manager Michael Caputo, are also defendants in the case.

“I want Roger Stone to be my first witness,” Redlich said.

Jury selection for the two to three day trial was expected to start Wednesday afternoon.

Opening statements are set for as early as Thursday afternoon. If Stone does not show up, he’s facing a possible warrant directing a sheriff to bring him to court, a $150 fine or a forfeiture of his defense.

​When told about the judge’s order Stone told The Post that he’ll comply with the subpoena.