As U.S. Ambassador Gordon Sondland prepares to defy the State Department and testify in an impeachment inquiry this week, the Portland-based hotel chain he founded is going on the offensive against a congressman who called for a boycott.

Last week, U.S. Rep. Earl Blumenauer (D-Portland) called for a boycott of Provenance Hotels, where where Sondland served as CEO until President Donald Trump appointed him U.S. ambassador to the European Union in 2018. Blumenauer said Americans should boycott Provenance properties—including six hotels in downtown Portland—until Sondland testified in a congressional impeachment inquiry.

Provenance's principal and president Bashar Wali filed an Oct. 11 federal ethics complaint against Bluemanauer, alleging the congressman violated the House Ethics Manual.

In the complaint to the House Ethics Committee, Wali points to a prohibition against members of Congress seeking reprisal against a presidential administration official.

"This is a clear ethical violation," Wali writes. "Congressman Blumenauer's statement is an explicit threat that could potentially create economic harm to Ambassador Sondland, an administrative official."

Wali argues that by asking consumers to inflict economic harm on a company founded by Sondland, Bluemanauer is seeking reprisal for Sondland's actions in his appointed office. He compares the threat to an effort to enrich political allies using public office. "Indeed," Wali writes, "the corollary of using an office to cause harm or loss to a private business would also seem to be an unethical use of power in the spirit of the code of ethics."

Wali also notes that Sondland no longer occupies an executive role at Provenance, and that he hadn't refused to testify in the impeachment inquiry—he was blocked by the White House.

In the complaint, Wali also implies that Blumenauer's own donors—including several real-estate developers with hotel interests—could benefit from a boycott of Provenance.

Blumenauer's office could not be reached for comment.

At least one Portland company has already severed ties with Provenance: Salt & Straw, the artisanal ice-cream chain, announced Oct. 10 it is no longer providing ice cream to the hotels.

Sondland, meanwhile, is expected to testify on Oct. 17 over the objections of the State Department. He will discuss Trump's alleged efforts to persuade Ukranian officials to investigate the president's political opponents.