Editor's note: This story has been updated throughout.
PHILADELPHIA — A contentious scene unraveled here Tuesday morning at a meeting of Texas delegates after one criticized Hillary Clinton, the presumptive Democratic presidential nominee and a favorite of Lone Star State Democrats.
The tension erupted while delegates supporting Bernie Sanders, Clinton's primary rival, were arrayed on the stage at a daily breakfast convened by the state delegation. It was meant to be a show of unity, with one of them, Russell Lytle of Denton, speaking hopefully of dialogue with Clinton supporters.
However, several minutes into his remarks, Lytle took a sharp turn against Clinton in what other Sanders delegates later described as an isolated incident.
"We want to be clear," Lytle said. "We are currently condemning our current presumptive nominee."
That touched off an angry reaction from some in the crowd, sparking loud boos and bringing Clinton backers to their feet. One of the people who rose pointed his finger at the stage.
"Stop this nonsense!" he said. "You need to grow up!"
Former Land Commissioner Garry Mauro, the Clinton campaign's top representative in Texas, took the microphone and tried to calm the room. He asked Clinton loyalists like himself to remember what it was like in 2008, when they arrived at the Democratic National Convention facing pressure to support presumptive nominee Barack Obama.
Texas Democrats, Mauro said, need to put their egos aside as they welcome new people to the party. That did not go over well with some Clinton supporters in the crowd, who said Sanders had lost and it was his backers who need to put aside their egos.
Lytle ultimately left the stage, where he could be seen speaking with state Sen. Royce West of Dallas, a longtime Clinton supporter. Approached by reporters, Lytle said his beef with Clinton is rooted in what he sees as a less-than-open nominating process.
The conflict led to Lytle voluntarily turning in his convention credential, according to state party officials. That's a largely symbolic move.
"In a moment of passion, while reaching out to my fellow members of the Texas delegation, I spoke one sentence that did not reflect my intention of promoting productive dialogue," Lytle said in a statement issued after the breakfast. "I apologize for my poor choice of words, and hope we can continue to move forward and work together towards the common goal of turning Texas blue."
Once the brouhaha died down at the breakfast, another Sanders delegate, Jen Ramos, took the stage for remarks that were much more well received.
"On behalf of the Bernie Sanders campaign, don’t cast off everyone just yet," said Ramos, who is from Austin. "While I am a Bernie Sanders delegate, I am first and foremost a Democrat."
With the crowd still buzzing about the dustup, state party Chairman Gilberto Hinojosa came to the stage and suggested that Lytle's remarks were unexpected. “What you heard was not what was supposed to be said," Hinojosa told the delegation.
Hinojosa then introduced Ashley Rodriguez, a Sanders delegate who said Sanders supporters "don't support any negative language" but begged Clinton delegates to be respectful.
"We can’t fight negativity with negativity," said Rodriguez, who is from El Paso. "That’s not how you’re going to achieve unity. You’re just not."
Later, Jacob Limon, who was Sanders' Texas director during the primary, said there was unity in the delegation "after the dust settled."
"So I think it was a cathartic moment that will pretty quickly turn into a unified effort," Limon said.
State party officials also announced that Sanders will address the Texas delegation on Wednesday.
Watch video of the breakfast below.