U.S. President Donald Trump admitted talking about corruption with Ukrainian President Volodymyr Zelenskiy, but stopped short of saying they talked about investigating 2020 leading Democratic presidential candidate Joe Biden.

A Wall Street Journal report says Trump urged Zelenskiy eight times to investigate Biden and his son Hunter, and whether a Ukrainian gas company tried to win favors by hiring Hunter while Joe Biden was U.S. vice president.

The reports say Trump was looking to get Zelenskiy to collaborate with Trump’s lawyer, Rudolph Giuliani, to investigate the Bidens.

Trump telephoned Zelenskiy in July, two months after he took power in Ukraine.

“The conversation I had was largely congratulatory, was largely corruption…and largely the fact that we don’t want our people, like Vice President Biden and his son creating to the corruption already in the Ukraine,” Trump said Sunday.

He said the White House will “make a determination” whether to release a transcript or details of the telephone call.

Ukrainian Foreign Minister Vadym Prystaiko denies Trump pressured Zelenskiy, saying Ukraine would not take sides in U.S. politics.

Joe Biden is seeking the 2020 Democratic presidential nomination, hoping to derail Trump’s re-election bid.

Trump critics, including a number of Democratic lawmakers, say if Trump urged Zelenskiy to investigate Biden to discredit the former vice president, that would be a direct appeal to a foreign government to interfere in a presidential election — a potentially impeachable offense. Democrats also want to know if Trump promised Zelenskiy anything in return for an investigation.

Trump had frozen $250 million in military aid to Ukraine. Congress voted to release those funds last month.

An angry Biden said “there is truly no bottom to President Trump’s willingness to abuse his power and abase our country.” Referring to next year’s election, Trump knows “I’ll beat him like a drum” Biden said.

“I’m not looking to hurt him with respect to his son. Joe’s got enough problems,” Trump said Sunday without specifying what those problems are.

The newest controversy surrounding Trump began last week when reports emerged that an unidentified whistleblower in the national intelligence community became alarmed about a series of actions inside the Trump administration. They include what is now known to be Trump’s telephone call with Zelenskiy.

This person contacted the intelligence inspector general, who called the complaint “serious” and “urgent.”

But acting National Intelligence director Joseph Maguire has refused to turn over the inspector’s report to Congress, which the law requires him to do.

Trump says he does not know who the whistleblower is, but called that person “partisan” and committing “just another political hack job.”

But congressional Democrats want to know why the inspector general’s report is being kept from them if Trump did not do anything wrong and want to know who Maguire and the Justice Department may be trying to protect.

Trump is also accusing Democrats and the media of avoiding the reports about Joe and Hunter Biden’s Ukrainian ties.

“The Fake News Media and their partner, the Democrat (sic) Party, want to stay as far away as possible from the Joe Biden demand that the Ukrainian Government fire a prosecutor who was investigating his son, or they won’t get a very large amount of U.S. money, so they fabricate…a story about me.”

As vice president under Barack Obama, Joe Biden went to Ukraine in 2016 and threatened to withhold billions of dollars in U.S. loan guarantees unless the government cracked down on corruption. Biden also demanded that Ukraine’s chief prosecutor Viktor Shokin be fired.

Shokin had previously investigated the gas company on which Hunter Biden served on the board. But the probe had been inactive for a year before Joe Biden’s visit. Hunter Biden has said he was not the target of any investigation and no evidence of any wrongdoing by the Bidens has surfaced.

Wayne Lee contributed to this report.