 -- Treasury Secretary Steven Mnuchin praised President Trump over his meeting with Russian leader Vladimir Putin, saying Trump “handled it brilliantly.”

“What started out as a 30-minute meeting lasted over two hours,” Mnuchin told ABC News Chief Anchor George Stephanopoulos on “This Week” Sunday. “And I think what we should be focused on was that the president handled it brilliantly.”

He said Trump “fully addressed” the issue of Russia’s alleged interference in the U.S. election during the meeting with Putin on Friday at the G20 summit, along with other key issues.

"He focused on the cease-fire in Syria, which is a major accomplishment. He talked about Ukraine and he talked about North Korea. So this was a very substantive meeting,” Mnuchin said on "This Week."

Stephanopoulos also asked if the president accepted the Russian leader's denial of having meddled in the U.S. election.

Mnuchin replied, "Why would President Trump broadcast exactly what he said in the meeting? Strategically that makes no sense."

"He's made it very clear how he feels, he's made it very clear that he addressed [alleged election interference] straight on, and there was significant substance," Mnuchin said.

White House Chief of Staff Reince Priebus was also asked Sunday if the president accepted Putin's denial, and said Trump "absolutely did not believe" Putin's assertion that Russia did not interfere in the U.S. election.

"The president absolutely did not believe the denial of President Putin," Priebus said on "Fox News Sunday." "What the president did is he immediately came into the meeting, talked about Russia meddling in the U.S. election, went after that issue at least two separate times. This was not just a five minute piece of the conversation."

Mnuchin also discussed with Stephanopoulos the possibility of additional sanctions against Russia. Trump tweeted this morning that he did not discuss sanctions in the meeting with the Russian president, adding, "Nothing will be done until the Ukrainian & Syrian problems are solved!"

When pressed by Stephanopoulos on whether that means additional sanctions against Russia are off the table, Mnuchin said, "We have sanctions that are already on the table and we expect to enforce those sanctions."

On the topic of tax reform, Stephanopoulos asked Mnuchin about an Axios report on White House chief strategist Steve Bannon proposing tax hikes for the wealthy. Mnuchin told Stephanopoulos, I have never heard Steve mention that. It's another example of a false leak that's being reported."

The treasury secretary said the White House is "absolutely committed to getting tax reform done this year."

"Our plan is to have a full-blown release of the plan in the beginning of September, with being able to vote and getting this passed before the end of the year," said Mnuchin.