NBC News was aware of video footage of Donald Trump making lewd and disparaging remarks about women for nearly four days, a network executive said Saturday, but delayed reporting about the story out of concern that Trump would sue the network.

The delay led to an awkward result: NBC News was scooped by The Washington Post, which took just five hours to vet and post its story. The Post acted on a tip from a source who was apparently frustrated by NBC's procrastination over airing perhaps the most consequential story of the 2016 presidential campaign.

The disclosure of Trump's unguarded comments, which were made while he was wearing a microphone for an interview on "Access Hollywood" in 2005, has led to calls for him to step down as the Republican nominee. Trump, who squares off against Hillary Clinton on Sunday in the second presidential debate, has vowed to remain in the race.

NBC News first became aware of the footage late Monday after receiving notice from producers at "Access Hollywood," a syndicated entertainment-news program owned by NBC. The program's producers had combed their archives for interviews with Trump after reading an Associated Press account of crude remarks he had made about female contestants on "The Apprentice," the NBC reality program that Trump had starred on for 14 seasons.

They found the 2005 segment, in which Trump and "Access Hollywood" co-host Billy Bush banter crudely about women while traveling to a studio taping.

By Tuesday morning, NBC News determined that the footage was newsworthy, and began to prepare a story. The news division agreed to let "Access Hollywood" break the story first, given that it had shot and unearthed the tape, according to an NBC executive who agreed to give the network's account on condition he not be named or quoted directly.

But the tape languished, unseen by the public, for several days after it first came to light.

Although NBC and "Access" both recognized the newsworthiness of the tape and intended to air it, it first had to undergo a review by the company's lawyers, the executive said. The executive was unaware of any specific legal issue raised by airing an 11-year-old recording of a presidential candidate who was apparently aware at the time that he was being recorded by a TV program.

However, the network was concerned that Trump could take legal action; the Republican nominee threatened to sue NBC last year after the network's entertainment division dropped plans to air the Miss USA beauty pageant in the wake of Trump's inflammatory remarks about Mexican immigrants. Trump backed off those threats when NBC sold its share of the pageant's rights to him in September 2015.

Although the news division had nearly completed its work on the story by Friday morning, the story was still not scheduled to air by then. "Access Hollywood," a daily program, had also not established an air date for its piece.

At that point, a still-anonymous source forced the issue. The source called Washington Post reporter David A. Fahrenthold around 11 a.m. Friday morning and pointed him to a copy of the tape on which Trump brags to "Access Hollywood" co-host Billy Bush that his celebrity status entitles him to grope women.

The Post reported and posted its story within five hours. NBC News, tipped that The Post story was imminent, finally decided to go with the story it had been holding all week. It waited until The Post's account was online and aired its story on MSNBC seven minutes later. "Access Hollywood" broadcast a piece later that evening.

The network executive said he does not know who The Post's source was, but noted that numerous people had access to the footage throughout the week, including employees of "Access Hollywood," NBC News and NBC's corporate staff.

He also would not speculate over the source's motives, but acknowledged that frustration over NBC's delay in airing it could have prompted the leak.

There are no plans, he said, to investigate the source of the leak within NBC's news division.