WASHINGTON — A US House panel issued a subpoena on Friday to Russian-born real estate developer Felix Sater after he failed to appear for a closed-door interview with the committee, which is interested in his work on a proposed Trump Tower project in Moscow.

Sater did not show up for a scheduled session with the House of Representatives Intelligence Committee. Numerous current and former Trump associates have refused to cooperate with congressional probes of Trump and his business interests.

Unexpected health issues prevented Sater from appearing, his lawyer Robert Wolf said.

"Due to health reasons Mr. Sater was unable to appear today. He looks forward to voluntarily appearing at the next rescheduled date," Wolf said in a statement.

Sater has voluntarily testified previously to the panel, as well as two Senate committees and U.S. Special Counsel Robert Mueller's staff, according to Wolf.

"Today’s issuance of a subpoena by the committee was entirely unnecessary," Wolf said.

But House Intelligence Chairman Adam Schiff appeared unmoved by Sater's health claim. "All I can tell you is that he agreed to appear this morning. He did not show up," he told reporters.

Representative Devin Nunes, the panel's top Republican, did not respond to questions from the press.

Committee spokesman Patrick Boland said in a statement: "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."

New York-based Sater, whose links to President Donald Trump were examined in Mueller's in-depth report on Russian meddling in the 2016 US election, worked with Trump's former lawyer Michael Cohen on a plan to build a Trump-branded skyscraper in Moscow while Trump was a presidential candidate.

The House Intelligence Committee wants to talk to Sater about his work on the project, which came under renewed scrutiny after Cohen pleaded guilty in November to lying to Congress about when negotiations on the deal ended in order to minimize Trump's links to Russia.

In late summer 2015, according to the Mueller report, Sater contacted Cohen, who was then a senior executive in the Trump Organization, about the project.

Sater had previously worked with Trump's company on other matters and had "served as an informal agent of the Trump Organization in Moscow," said the report, released in redacted form in mid-April after an almost two-year probe.

Trump's children Ivanka Trump and Donald Trump Jr. were accompanied by Sater when they visited Moscow in the mid-2000s.

In November 2015, Sater emailed Cohen suggesting that the Moscow project could be used to increase Trump's chances of getting elected, according to the Mueller report.

"Buddy our boy can become President of the USA and we can engineer it. I will get all of Putins team to buy in on this, I will manage this process," said the email quoted in the report.

"Michael, Putin gets on stage with Donald for a ribbon cutting for Trump Moscow, and Donald owns the republican nomination. And possibly beats Hillary and our boy is in .. . . We will manage this process better than anyone. You and I will get Donald and Vladimir on a stage together very shortly. That the game changer," the email said.

Later that day, Sater followed up in an email that said: "We can own this election. Michael my next steps are very sensitive with Putins very very close people, we can pull this off. Michael lets go. 2 boys from Brooklyn getting a USA president elected. This is good really good."

Mueller's 448-page report found insufficient evidence to establish that the Trump campaign engaged in a criminal conspiracy with Moscow, despite numerous contacts between the campaign and Russia. It also described numerous subsequent attempts by Trump to impede Mueller's investigation, but stopped short of declaring that he committed a crime. — Reuters