Just hours after a Catholic diocese in Kentucky threatened to expel several high school students accused of mocking Native Americans at a Washington rally in a viral video this week, new footage has emerged showing tension developing before the confrontation, as conservatives argued the original clip didn't tell the whole story.

At one point in the newly released footage, an off-camera voice was heard saying, "White people, go back to Europe where you came from," as Nathan Phillips, a 64-year-old Native American man, stood inches away from the students, banging a drum. Then, apparently the same voice said, "This is not your land." The full context of the quotes was unclear.

The run-up to the viral clip also appeared to show additional loud chanting from the students. An apparently unedited, nearly two-hour-long full video surfaced over the weekend.

By Sunday, the Republican congressman representing the students said they'd been treated unfairly.

The Indigenous Peoples March in Washington on Friday coincided with the March for Life, which drew thousands of anti-abortion protesters, including the group from Covington Catholic High School in Park Hills, Kentucky. Some videos circulating online showed a young person at the rally staring at Phillips, standing extremely close to him.

Other students, some wearing Covington clothing and many wearing "Make America Great Again" hats and sweatshirts, surrounded them, chanting, laughing and jeering.

The video clips prompted a fierce social-media backlash, including campaigns aimed at identifying and harassing the high school students. Actress and activist Alyssa Milano tweeted that the footage "brought me to tears," while actor Chris Evans tweeted that the students' actions were "appalling" and "shameful."

Phillips, speaking to The Detroit Free Press, claimed that the students were “in the process of attacking these four black individuals" when he approached.

Members of the Black Hebrew Israelites reportedly were present at the Lincoln Memorial as well, and Phillips told the paper that one of them had spit at the students. Others were "saying some harsh things," he said, and so he decided to "put myself in between that, between a rock and hard place."

However, the longer video led some conservative commentators to retract their previous criticisms of the students. The students did not appear to engage in any physical attack on any members of the Black Hebrew Israelites in the footage, although several individuals off-camera hurled racial and homophobic epithets at the students.

"I’ve now watched over an hour of other videos from 4 different cameras of the incident in front of the Lincoln Memorial. I urge everyone to watch the other videos before passing judgement. Would you have remained that composed at that age under those circumstances?" Rep. Thomas Massie, R-Ky., tweeted. "The parents and mentors of these boys should be proud, not ashamed, of their kids’ behavior. It is my honor to represent them."

A Princeton University professor and religious freedom advocate apologized in a tweet.

The extended video appeared to show one student charging downstairs at the Lincoln Memorial, taking off his shirt, and, facing his classmates, leading them in a cheer facing rival protesters -- which both included Native Americans and African-Americans, among others. Shortly afterwards, Phillips approached the crowd of students.

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"Here is a video clearly showing that Nathan Phillips approached the students," Catholic Herald columnist Matthew Schmitz tweeted Sunday. "On the basis of the evidence we now have, I believe that people who issued categorical and one-sided condemnations of the students should retract and apologize."

"Just watched the full, unedited video of the MAGA kid and the Native American vet," wrote Daily Caller writer Benny Johnson. "I’d like to amend this tweet. The kid did absolutely nothing wrong. I regret the error. It makes this assault by leftists I witnessed all the more sick."

It has also emerged that Philips, in 2015, reportedly claimed that he was harassed by college students wearing Native American garb.

In a joint statement this weekend prior to the new video circulating, the Roman Catholic Diocese of Covington and Covington Catholic High School apologized for the students' behavior. Officials said they were investigating and would take "appropriate action, up to and including expulsion."

"We extend our deepest apologies to Mr. Phillips," the diocese's statement read. "This behavior is opposed to the Church's teachings on the dignity and respect of the human person."

WARNING: FULL VIDEO CONTAINS PROFANITY

Marcus Frejo, a member of the Pawnee and Seminole tribes who is also known as Chief Quese Imc, said he had been a part of the march and was among a small group of people remaining after the rally when the boisterous students started performing the haka, a traditional Maori dance. In a phone interview, Frejo told The Associated Press he felt they were mocking the dance.

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One 11-minute video of the confrontation showed the haka dance and students loudly chanting before Phillips and Frejo approached them.

Frejo said he joined Phillips to defuse the situation, singing the anthem from the American Indian Movement with both men beating out the tempo on drums.

Although he feared a mob mentality that could turn ugly, Frejo said he was at peace singing despite the scorn.

"They went from mocking us and laughing at us to singing with us. I heard it three times," Frejo said. "That spirit moved through us, that drum, and it slowly started to move through some of those youths."

Eventually a calm fell over the group of students and they broke up and walked away.

As of Sunday morning, Covington Catholic High School's Facebook page was not available and its Twitter feed was set to private.

Oklahoma Republican Sen. James Lankford on Sunday condemned the apparent role of hate in the episode, which came just days after the House voted overwhelmingly to censure Iowa Rep. Steve King for questioning why the terms "white supremacist" and "white nationalist" were offensive.

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“The key issue that I would say is in our culture for whatever reason, in our current culture, whether it's on social media or at events, I see people trying to stop hate with more hate," Lankford told ABC News' "This Week."

"That doesn't help us as a culture," he continued. "If there's anything we should have learned from Martin Luther King Jr. is, hate doesn't drive out hate, only love drives out hate.”

Fox News' Paulina Dedaj, Andrew O'Reilly and The Associated Press contributed to this report.