U.S. President Donald Trump said on Sunday he had “nothing to hide” from the special counsel investigating Russian interference in the 2016 U.S. election, and denied that his top lawyer had turned on him by cooperating with the probe.

Trump, in a series of tweets, denounced the New York Times for a Saturday story saying White House Counsel Don McGahn has cooperated extensively with the special counsel, Robert Mueller. The Times said McGahn had shared detailed accounts about the episodes at the heart of the inquiry into whether Trump obstructed justice.

“I allowed him and all others to testify – I didn’t have to,” Trump said in a tweet. Trump said the newspaper made it seem like McGahn had turned on the president – as White House counsel John Dean had in the Watergate investigation of former President Richard Nixon – “when in fact it is just the opposite.”

As White House counsel since the beginning of the Trump administration, McGahn could have rare insight into the president’s thinking.

His lengthy testimony – 30 hours over three voluntary interviews, according to the Times – could be crucial in determining whether the president acted with an improper, or “corrupt,” intent when he took actions like firing former FBI Director James Comey, legal experts said. That is a key part to an obstruction of justice case.

Citing a dozen current and former White House officials and others briefed on the matter, the Times said that McGahn had shared information, some of which the investigators would not have known about.

On Saturday evening, McGahn’s lawyer confirmed the White House counsel had cooperated with Mueller’s team. “Mr. McGahn answered the Special Counsel team’s questions fulsomely and honestly,” William Burck said, explaining the president did not ask McGahn to refrain from discussing any matters.

Trump’s outside legal counsel, Rudy Giuliani, said McGahn’s cooperation would help bolster Trump’s claims that he did nothing wrong.

“The president encouraged him to testify, is happy that he did, is quite secure that there is nothing in the testimony that will hurt the president,” Giuliani said on NBC’s “Meet the Press.”

Dean, who has criticized Trump in recent years, voiced support for McGahn. “McGahn is doing right!” he wrote on Twitter.

According to the New York Times, McGahn described Trump’s furor toward the Russia investigation and the ways in which the president urged McGahn to respond to it.

As carried in R