Federal prosecutors scrutinizing President Trump’s personal attorney Rudolph W. Giuliani and two of his associates are to question a top executive of Ukraine’s state-owned gas company Thursday about his encounters with those associates as the pair pursued energy deals in Ukraine this year.

The executive of the Ukrainian company, Andrew Favorov, an American citizen, agreed to meet with prosecutors for the Southern District of New York who had asked to speak with him about his experiences with the two men, Lev Parnas and Igor Fruman.

The pair worked with Giuliani to gather information about the Ukraine-related activities of former vice president Joe Biden and his son Hunter.

Favorov’s attorney, Lanny Breuer, said his client “will voluntarily sit down with the government attorneys.” Breuer declined to comment further.

A spokesman for the U.S. attorney’s office for the Southern District of New York declined to comment. The prosecutors’ scheduled meeting with Favorov was first reported by the Associated Press.

The interest in Favorov, who serves as a top executive at the state-owned company Naftogaz, indicates that investigators are focusing on efforts by Parnas and Fruman to secure business deals for themselves in the historically corrupt Ukrainian energy sector while they were also assisting Giuliani’s work in that country.

Federal prosecutors have been examining Giuliani’s ties to the two men, who have been charged with violating U.S. campaign finance laws by allegedly helping to funnel foreign money to candidates and political committees. They have pleaded not guilty.

Giuliani has referred to Parnas and Fruman as clients, and he has said he was paid $500,000 to help advise a financial security company started by Parnas called Fraud Guarantee.

The two men also helped Giuliani’s efforts to investigate the activities of Hunter Biden, who served on the board of another Ukrainian energy firm. This year, the pair arranged a meeting between Giuliani and Ukraine’s former top prosecutor, Yuri Lutsenko, who allegedly offered information about the Bidens.

After Parnas and Fruman were arrested, Giuliani denied any knowledge of wrongdoing on their part. In an interview, he said that he had seen the two men “quite often” and had “no reason to believe that they are anything other than decent guys.”

Favorov met with Fruman and Parnas on at least two occasions this year, according to people familiar with his account.

The first encounter occurred on the sidelines of a Houston energy conference in March. The pair proposed to Favorov a deal to import liquefied natural gas and explored whether he would agree to replace the chief executive of the giant Ukrainian gas company, according to people familiar with the meeting.

One person who was briefed by Favorov on the Houston discussions, Dale W. Perry, an American gas executive, said that the pair told Favorov that then-U. S. ambassador to Ukraine, Marie Yovanovitch, was a likely impediment to such a plan.

Yovanovitch testified last week before House lawmakers that she saw Naftogaz’s current chief executive, Andriy Kobolyev, as a reformer fighting widespread corruption in the Ukrainian gas industry.

Parnas and Fruman assured Favorov that Yovanovitch would soon be removed from her post, Perry said.

Weeks later, on May 1, the men met again in Washington, where Fruman and Parnas again pitched a deal with Naftogaz, according to people familiar with Favorov’s account.

After the Washington meeting, Favorov was stunned when Yovanovitch was abruptly recalled from Kyiv, as Parnas and Fruman had predicted, the people said.

“If she can be removed, then anything is possible now,” Perry said in an interview with The Washington Post in October. “Where is the rule of law? Where is the stability?”

A lawyer for Parnas, Joseph Bondy, declined to comment. A lawyer for Fruman, Todd Blanche, did not respond to requests for comment.

Parnas and Fruman discussed Yovanovitch with Trump at a dinner for top super PAC donors at the Trump hotel in Washington in the spring of 2018, as The Post previously reported. The two men identified her as unfriendly to Trump’s interests, and the president in response suggested that she should be fired, according to people familiar with Parnas’s account of the dinner.

The scope of the federal investigation into the business activities of Giuliani and his associates is unclear. Earlier this year, federal prosecutors in Chicago pursuing an unrelated case against Dmytro Firtash, a Ukrainian gas tycoon accused of bribery, had come across Parnas and Fruman offered assistance to their counterparts in New York, The Post previously reported.

Last summer, Parnas started working as a translator for Firtash’s legal team, according to Victoria Toensing, one of Firtash’s lawyers. Firtash has been accused by federal prosecutors of having ties to Russian organized crime and has been fighting extradition to the United States from Austria. Firtash has denied such ties and any wrongdoing.