The incident occurred as both men headed to their seats during the summit being held in Osaka, Japan.
The South Bend, Indiana mayor made the remarks in response to the suggestion he is "too young, too liberal [and] too gay" to be president.
The husband of Trump advisor Kellyanne Conway called for the president to resign and seek professional help.
"Impeachment polls right up there with skim milk among the American people," Sen. John Kennedy (R-La.) said.
"Mueller, I'd imagine, at the behest of the left gives them what they need to jumpstart the calls for impeachment," Jeanine Pirro said. "You either indict or you don't… every prosecutor knows if you don't indict someone, you stop there."
"We have a constitutional republic to uphold liberty and the Rule of Law, not a direct democracy to serve some at the expense of others," Rep. Justin Amash (R-Mich.) said.
"A lot of people are moving here. So, what can I say? No, I didn't know that [Meghan Markle] was nasty," President Trump told British Tabloid The Sun in an interview ahead of his visit to the U.K.
"LGBTQ people deserve to live, work, raise families, and succeed just like anyone else ," Gillibrand wrote.
"This isn't even a close case," former federal prosecutors said in a video.
Aryan Nations is a "longstanding neo-Nazi group in the United States" that includes the religious faction Christian Identity, a "small, virulently racist and anti-Semitic religious sect prominent in the extreme right."
"Under an agreement that they had before today's ruling, there are seven days," CNN correspondent Kara Scannell said.
"Right now, I'll never rule anything out," Trump Jr. told Fox News host Sean Hannity in March when asked if he planned to run.
The official Korean Central News Agency published a commentary Tuesday castigating Biden, who "dared to blaspheme our dignity in the election campaigns."
"Within the White House there is a lot of conflicting opinions," said Hossein Amir-Abdollahian, the director of foreign affairs for the Iranian parliament.
The comments were not the first time the president has suggested extending his constitutional term limits.
Fox News "got dumped from the Democrats boring debates, and they just want in. They forgot the people who got them there," Trump said.
Counselor to the President Kellyanne Conway's husband George Conway accused Trump of lying multiple times on Sunday.
John McAfee, who is running his campaign from the Bahamas, compared paying income taxes to slavery and said Americans are "hated universally."
"Both have conducted two train-wreck campaigns, and both seem to have lived a politically cursed public life," Lewandowski claims of Biden and Clinton.
Former federal prosecutor Jack Weiss compared Michael Flynn's voicemail recording to Trump's "Access Hollywood" tape in 2016. "If we get a live tape, I think it'll be a big deal," he said.
"I just heard that the worst mayor in the history of New York City... is now running for president," Trump said in a video uploaded to Twitter.
The president noted that while some people may have a problem with Buttigieg's gay marriage, he has "no problem with it whatsoever" and thinks "it's good."
Michael D'Antonio, a CNN contributor who wrote the book "The Truth About Trump," offered his insights into the president's background in evading procedure and protocol.
If Congress won't work with her, Senator Harris plans to go it alone on an assault weapons ban should she ascend to the White House next fall.
Newman filed courts papers on Monday seeking to join former Trump campaign staffer Alva Johnson's lawsuit, which accuses Trump of attempting to forcibly kiss her in August 2016 and his campaign of gender pay discrimination.
"I wanted to see Hillary Clinton win," Stern said. "If she had come on the show — the way I helped Donald was I let him come on and be a personality."
Gary Joseph Gravelle, 51, from New Haven, sent a threatening letter addressed to President Trump that contained a white powder he claimed was anthrax.
"This isn't foreign policy—I'm asking them to do an investigation that they're doing already and that other people are telling them to stop."
Buttigieg subtlety criticized President Trump as someone that cannot deal with change through a Chinese proverb that referenced building windmills and walls.
"He is trying to prevent Congress from doing its oversight function and we won't accept that," Rep. Jackie Speier (D-Calif.) said.