US presidential candidate Donald Trump has apologised for obscene comments about women he made in a newly released videotape from 2005.
Trump said that "these words don't reflect who I am... I apologise".
In the video, Trump says "you can do anything" to women "when you're a star" and brags about trying to grope and kiss women.
Top Republicans condemned the comments. His election rival Hillary Clinton called them "horrific".
"We cannot allow this man to become president," she posted on Twitter.
Trump's 90-second statement on Saturday morning appeared to be his first full apology in a campaign laced with controversial remarks.
"I've said and done things I regret," he said. "Anyone who knows me knows these words don't reflect who I am. I said it, I was wrong, and I apologise.
"I've never said I'm a perfect person nor pretended to be someone I'm not. I pledge to be a better man tomorrow."
However, he also tried to deflect the impact by attacking former President Bill Clinton.
"Bill Clinton has actually abused women, and Hillary has bullied, attacked and shamed his victims.
"We'll discuss this in the coming days," he said. "See you at the debate on Sunday."
The second TV debate between Trump and Hillary Clinton will take place on Sunday evening in St Louis.
Trump recently said he would not bring up stories about Bill Clinton's infidelities in the debate, after previously threatening to do so.
The latest opinion polls suggest Clinton is pulling ahead in key battleground states and Trump will need a good performance at the debate to slow the trend.
'I moved on her'
In the video, posted by the Washington Post, Trump is heard bragging to TV host Billy Bush about trying to have sex with a married woman as well as kissing and groping others.
The clip was part of unaired footage of an Access Hollywood segment ahead of Trump's appearance on the soap opera Days of Our Lives.
"I moved on her and I failed. I'll admit it," Trump is heard saying. "She was married. And I moved on her very heavily.
"I moved on her like a bitch, but I couldn't get there. And she was married. Then all of a sudden I see her, she's now got the big phony tits and everything. She's totally changed her look."
Later in the conversation, he told Bush he was "automatically attracted to beautiful" women and often tried to kiss them.
"I just start kissing them," he said. "I don't even wait. And when you're a star, they let you do it. You can do anything."
Top Republicans have been incensed by the comments.
House Speaker Paul Ryan said he was "sickened by what I heard today" and rescinded his invitation to Trump to attend the Republican Fall Fest in his home state of Wisconsin this weekend.
Senate majority leader Mitch McConnell said the comments were "repugnant," adding that Trump "needs to apologise directly to women and girls everywhere".
Another senior Republican, John McCain, said there were "no excuses for Donald Trump's offensive and demeaning comments".
For his part, Billy Bush said he was "embarrassed" by and "ashamed" of the contents of the video.
"It's no excuse, but this happened 11 years ago. I was younger, less mature, and acted foolishly in playing along. I'm very sorry."
Trump has said the latest remarks are "nothing more than a distraction" and "locker-room banter".
He once famously said at a campaign rally in January: "I could stand in the middle of 5th Avenue and shoot somebody and I wouldn't lose voters."
He will be hoping his latest comments follow that trend.