Las Vegas (CNN) Michael Bloomberg remained a target of his Democratic presidential rivals Thursday night, as former Vice President Joe Biden and Sen. Elizabeth Warren of Massachusetts harshly criticized the former New York City mayor during CNN town halls in Las Vegas .

Their criticism came the day after Bloomberg was assailed for his past support for stop-and-frisk policing, offensive remarks he's accused of making about women, and more in his first appearance on the Democratic presidential debate stage.

Here are four takeaways from the Biden and Warren town halls:

Warren hits Bloomberg's nondisclosure agreements again

Warren opened her town hall by keeping up her attacks on Bloomberg for refusing to release women who have signed nondisclosure agreements at his company, saying they should be able to tell their stories.

She arrived onstage with a draft release document that she said she had written and would send to Bloomberg.

"So I used to teach contract law. And I thought I would make this easy. I wrote up a release and covenant not to sue. And all that Mayor Bloomberg has to do is download it. I'll text it," she said. "Sign it. And then the women, or men, will be free to speak and tell their own stories."

Warren next read aloud, verbatim, what the document said. Then she added: "I think that the mayor should sign this and that we all have a right to see."

She said that failing to release the women from the nondisclosure agreements would be "disqualifying" for Bloomberg. But, when pressed by CNN's Erin Burnett, Warren said she'd still vote for him over President Donald Trump.

'Barack's best buddy'

Biden, meanwhile, took issue with the more than $400 million Bloomberg has spent on advertising -- with spots featuring former President Barack Obama praising the billionaire.

"He's advertising himself to be Barack's best buddy," Biden said, referring to Bloomberg's ads that feature Obama's voice praising him.

But, Biden said, the former mayor had opposed Obamacare and was at odds with the Obama administration on Bloomberg's controversial stop-and-frisk policing policy.

"And the way he refers to people of color. ... I'm not even going to repeat the language he used about why he was doing this," Biden said.

Like Warren, he lambasted Bloomberg for failing to release the women at his company who had alleged misconduct from nondisclosure agreements.

"It's just wrong," Biden said. "How can you run against Donald Trump when you have, what is it, 10, 12, 14 NDAs?"

Biden hits Sanders on guns

Biden also criticized Sen. Bernie Sanders, saying the Vermont independent has not lived up to his rhetoric on guns and has not done enough about the issue. He pointed to Sanders' 1990s votes against gun control measures, when Sanders was in the House of Representatives.

The comments at his CNN town hall built on comments Biden had made earlier in the day, when he called out Sanders -- by name -- for opposing the Brady Act, which mandated federal background checks and a waiting period for some handgun purchases.

"It is not so much what you say you believe," Biden said. "It is what did you do and when did you do it."

He added: "The fact is Bernie has had a very different record than me for a long time. For example, I am the guy, as chairman of the Judiciary Committee, worked to pass very difficult legislation. The Brady Bill, which had background checks, as well as waiting period. Bernie, when he was running for the Senate of Vermont and said it was a tough state to run in, he voted against it five times in the House of Representatives."

Biden then hit Sanders for voting to "exempt gun manufacturers from any liability. Zero. They cannot be sued."

Warren keeps on poking at Sanders

Warren has spent the last couple of days lighting up Bloomberg, but she's also taken more subtle swipes at Sanders.

On Thursday night, Warren continued on that path, questioning how any candidate -- "including Senator Sanders" -- plans to execute on their vision without blowing up the Senate filibuster. Later on, she suggested that Sanders would have trouble bringing together Democratic factions and other voters outside the party to defeat Trump in November.

Democratic voters, she said, "are nervous about a narrow vision that just doesn't speak to the Americans who see real problems and want to see real change. But they are also worried about gambling on a revolution that won't bring along a majority of this country." She didn't name Sanders then, but the implication was clear.

"I am a Democrat, through and through," Warren added. "I have rock-solid values and I know how to get things done. I speak to all parts of our party and with things like the wealth tax, speak to independents and Republicans."

Her criticisms came after she cast doubt on Sanders' strategy -- or lack thereof -- for delivering on his "Medicare for All" plan and did not let him off the hook over his medical records, saying he "had made a promise to release all his medical records and I thought that was what he was going to do."