MOSCOW — Ukraine’s top anti-corruption official said Friday his agency hasn’t launched an investigation into former U.S. Vice President Joe Biden or his son, even though U.S. President Donald Trump pressed for one in a summer phone call that has touched off an impeachment inquiry.

Trump pushed Ukrainian President Volodymyr Zelenskiy to investigate his political rival and his son, Hunter, who served on the board of an energy company in Ukraine. That July 25 phone call is the focus of a whistleblower complaint that triggered the formal impeachment inquiry in the U.S. Congress.

Nazar Kholodnitskiy, the head of the Specialized Anti-Corruption Prosecutor’s Office, said in an interview with NV radio that Biden and his son weren’t the subject of any investigation.

Hunter Biden served on the board of Ukrainian gas company Burisma at the same time as his father was leading the Obama administration’s diplomatic dealings with Kyiv.

Though the timing raised concerns among anti-corruption advocates, there has been no evidence of wrongdoing by either the former vice president or his son.

Trump also has claimed that Joe Biden pressured the Ukrainian government to shut down a corruption investigation of Burisma, but that claim has been repeatedly discredited.

Kholodnitskiy said in a radio interview that the earlier investigation of Burisma was closed for lack of evidence in 2017, but a court in the Ukrainian capital overruled the move the following year.

Despite the court’s ruling, the case has remained on hold and the investigation has stalled.

He emphasized that there was no mention of Biden or his son in the Burisma case, which was focused broadly to look into alleged abuse of power by officials in Ukraine’s Ministry of Ecology.

Asked if Ukrainian prosecutors could question Biden or his son, Kholodnitskiy said that to do so they would need to see information that would signal possible wrongdoing. “As of now, there is nothing there,” he said. “If it comes up, measures will be taken to check the information.”

In the July call, Zelenskiy appears to make an effort to stay in Trump’s good graces, telling him at least twice that he is “absolutely right.” But after the rough transcript was released by the White House this week, Zelenskiy told reporters he didn’t feel pushed, emphasizing that “no one can pressure me.” He also sought to play down the situation involving Biden and his son’s activities in Ukraine, calling it just one of “many cases that I talk about with leaders of other countries.”