The House Intelligence Committee will issue a subpoena for the testimony of Felix Sater, who worked in 2016 on a proposed Trump Tower development in Moscow, after he failed to appear on Friday for a scheduled interview with panel staff.

“The Committee had scheduled a voluntary staff-level interview with Mr. Sater, but he did not show up this morning as agreed. As a result, the Committee is issuing a subpoena to compel his testimony,” panel spokesman Patrick Boland said in a statement.

But Sater’s attorney, Robert Wolf, said Friday that his client had failed to show up because of health complications — and stands ready to appear voluntarily at any time.

“Today’s issuance of a subpoena by the Committee was entirely unnecessary,” Wolf said. He said he told the committee that Sater woke up late “due to the effect of his health-related condition.”

Sater was “looking forward to his voluntary appearance today, his second before this Committee,” Wolf said. “He was extremely disappointed when the Committee previously cancelled his April 10th voluntary public interview. Mr. Sater’s record of cooperation is undisputed and exemplary.”

A committee staffer said the panel was not informed of any health reasons for Sater’s failure to appear. In addition, the committee maintains that Sater did not provide requested documents. Wolf disputed those claims.

Sater, a Russian-born real estate developer, has attracted the attention of federal investigators looking into Trump’s Russia ties because of his role in trying to advance two separate Trump Tower projects in Moscow — one in 2005 and another during the 2016 election.

Neither project got off the ground, but the president’s interest in expanding his brand into Russia — and the fact that a subordinate initially misrepresented to lawmakers how long he pursued the potentially lucrative project — has been a key area of interest to House Intelligence Committee’s Chairman Rep. Adam B. Schiff (D-Calif.) before and after the release of the report by special counsel Robert S. Mueller III.

During an appearance Wednesday at the National Press Club in Washington, Schiff said that although negotiating with the Russians while running for office may not be a matter for prosecutors, it could have made Trump vulnerable to foreign influence.

“It may not be a crime,” he said. “It is, however, a counterintelligence problem of the first order of magnitude.”

Sater was of interest to investigators because of his year of working with Trump and his connections in Moscow. In addition to working on the two Trump Tower projects in Russia, Sater also escorted Trump’s children, Ivanka Trump and Donald Trump Jr., around the Russian capital during a 2006 visit.

The panel gave no further details Friday about the terms of the subpoena or when they planned to demand Sater appear to deliver his testimony.