Sen. Susan Collins, R-Maine, says President Donald Trump needs to "step back" and not comment on special counsel Robert Mueller's investigation into Russian meddling in the 2016 election.

"I understand how difficult and frustrating this investigation is for the president. But he should not say anything further about the special counsel, his staff or the investigation," Collins said Sunday on CBS News' "Face the Nation."

"I know it's hard, but he needs to step back and not comment, and let Bob Mueller who is an individual with the utmost integrity, carry out the investigation and make his determination," she added.

Collins' remarks follow comments Mr. Trump made in an interview with The New York Times about the Russia probe. He said he felt it was unfair for Attorney General Jeff Sessions to recuse himself from the Russia investigation, and that Sessions should have told Mr. Trump if he was going to recuse himself before he accepted the position.

Collins said she disagrees with the president.

"The attorney general followed the rules and guidelines of the Department of Justice," she said. "He met with career staff, and he made the right decision in recusing himself."

When pressed on new reports alleging that Sessions' answers to the Senate Intelligence Committee's questions regarding his interactions with Russian entities may not have been complete, Collins said that the committee will "follow any credible allegation as part of our investigation."

Sen. Susan Collins on "Face the Nation," July 23, 2017. CBS News

The Washington Post reported on Friday that former Russian Ambassador Sergey Kislyak told his superiors that he discussed campaign-related issues with Jeff Sessions during the 2016 race for the White House. The report cited current and former U.S. officials.

A former U.S. intelligence official told CBS News on Saturday that the Post's story is accurate. U.S. intelligence intercepted electronic communications between then-Ambassador Kislyak and the Ministry of Foreign Affairs in which Kislyak said he and Sessions discussed campaign issues at meetings the two men had.

However, a former U.S. official said it is possible Kislyak was lying about his conversations with Sessions, CBS News' Jeff Pegues reported.

On Sunday, Collins said, "I would point out that there is a big difference between an unsubstantiated leak about an alleged intercept versus sworn testimony and facts. And our focus is on sworn testimony, and getting all the facts."

She added, "the Russian ambassador is our adversary, and the Russians have shown themselves to be masters at misinformation. Nevertheless, that's clearly a scenario that we need to pursue further."

She noted that the intercept, if accurate, has the potential to "compromise our national security and to undermine the safety of those who are in the intelligence community."