Minneapolis school district and union officials did not meet for in-person mediation on Wednesday after talks to end a teacher's strike now in its third week stalled the previous night. But the conflict continued to intensify.

District administrators said the union on Tuesday brought a counterproposal that was millions of dollars more costly than their previous offers — a sign of backwards movement, they said. Meanwhile, union leaders said they've come way down from previous teacher wage proposals and that district leaders were the ones who left the table Tuesday night.

Further fueling the clash: a publicized string of text messages between a union president and a member of the district's negotiating team. Also Wednesday, a group of just over two dozen students stayed at the district headquarters into the evening with a list of demands similar to those of the teacher's union, while a group of parents gathered in support of the district's position.

A local education blog posted an article Wednesday with screenshots of texts sent in late January by Eric Moore, the district's head of accountability, research and equity, to Greta Callahan, the president of the union's teacher chapter. The article, published on Bright Light Small City, claims the messages suggest Moore is gunning for the superintendent job, currently held by Ed Graff. Graff's new contract has not yet come before the school board, which voted 5-4 in October to renew the agreement.

Both Moore and Callahan confirmed to the Star Tribune that the messages in the article were ones they sent and received. Callahan also confirmed she brought the messages to Graff's attention in late February.

Callahan declined to comment further. Moore called the blog post "gross" and "disappointing."

"The mudslinging has gotten so low," Moore said in a brief conversation with the Star Tribune, adding that the texts were "taken out of context." He did not elaborate.

The district issued a statement after the texts were publicized.

"The timing of the visibility being given to a series of text exchanges from eight weeks ago is at least curious, but perhaps very intentional, given the current status of negotiations to end the strike," it read.

The district's general counsel was made aware of the texts and investigated the exchange before determining no laws were broken, according to the statement. Counsel also advised that the "clear priority" was to keep focus on settling the contracts with Minneapolis teachers and support staff, the statement said.

By Wednesday evening, district leaders were in a virtual mediation session to work toward a tentative agreement with the union's educational professional chapter.

The next mediation session with the union's teacher chapter has not been scheduled, according to union and district officials. The district on Sunday presented what it called its "last, best and final" offer for educational support professionals — one that union leaders said didn't do enough to meet their priority of ensuring a $35,000 starting wage.

The union's latest teacher wage proposal offers an overall 3% increase in the first year, a 3% increase in the second year and a $5,000 bonus for all teachers, according to an update on the union website.

The update also said the district's offer would give teachers with one to six years of experience wage increases of 5% to 12.5% in the first year, with the larger amounts going to those with less experience. All other teachers would get a 2% boost. In the second year, the district would offer a 2.25% boost for all teachers. All teachers would also receive a $2,000 bonus in the contract's first year and $1,000 in the second year.

"We offered teachers our last, best, final offer and are waiting for them to work within our parameters," School Board Chair Kim Ellison said. Callahan pushed back, saying the union's latest offer fit within those limits but that the hang-up comes from the district's hesitation to put some agreements in contract language.

"I am deeply terrified about the leadership in this district," Callahan said. "And the extent they're willing to go, and who they're willing to harm, to continue to withhold total power."

Dozens of students held another sit-in at district headquarters Wednesday. They gathered in the morning as teachers picketed outside in the snow.

By Wednesday afternoon, the district building was full of students orchestrating a sit-in. Meanwhile, a separate demonstration of about 20 parents pressured the school district to give into the union's demands and end the strike. Teachers continued to picket outside.

Southwest High School seniors Emi Gaçaj and Don Newell of the Coalition of Student Leaders said the sit-in would go all night to send a message to district leaders to meet the teachers' demands. The group is especially vocal about increasing funding for poorer schools and for more help for students of color.

"The district likes to ask, 'What about the students?' " Gaçaj said. "Well, we are the students, and we're here showing up and fighting for our list of demands."

As of Wednesday evening, Newell said students were planning to stay in the building even though it closes at 8 p.m.

In a statement, the district said it "respects students' First Amendment right to peacefully assemble, and we support students using their voices to stand up for what they believe in."

Several Minneapolis Public Schools staff members spoke with students, according to the statement.

Helena Kouame, a senior at South High School, packed a sleeping bag when she arrived at district headquarters, prepared to stay overnight.

"This is the students' idea. This is our occupation," she said. "We just wanted to make it powerful because it feels like no action has been made, no progress has been made."

Star Tribune staff writer Alex Chhith contributed to this story.