Former FBI Deputy Director Andrew McCabe says he ordered an obstruction of justice investigation into President Donald Trump after Trump fired FBI Director James Comey in 2017 to ensure the Russia probe wouldn't "vanish in the night without a trace."

"I was very concerned that I was able to put the Russia case on absolutely solid ground in an indelible fashion that, were I removed quickly or reassigned or fired, that the case could not be closed or vanish in the night without a trace," McCabe told CBS News in a partial interview clip aired Thursday.

While it had been previously reported that an obstruction of justice probe had been opened as part of special counsel Robert Mueller's Russia investigation into possible collusion between the Trump campaign and Russia, McCabe's disclosure was the first time he publicly addressed why he launched the investigation. McCabe's interview with "60 Minutes" is set to air in full on Sunday.

McCabe didn't reference specific evidence that prompted the investigation during the clip, but he said he "wanted to make sure that our case was on solid ground and if somebody came in behind me and closed it and tried to walk about from it, they would not be able to do that without creating a record of why they made that decision."

Comey's firing in May 2017 set off a round of speculation into the president's motive for doing so. McCabe, who became acting director following the dismissal and returned to his prior role as deputy when the Senate confirmed Christopher Wray to lead the bureau, became a lightning rod for those who sought to discredit the bureau's Russia investigation and review of Hillary Clinton's emails. He was fired from the bureau in March just hours before he could retire.

In the clip, McCabe recalled his first meeting with Trump, saying he felt "troubled" by the circumstances.