After uproar over kids' enduring cold schools, fundraising and repairs underway "We are working around the clock," the mayor said.

 -- After photos circulated widely on social media this week of Baltimore schoolchildren huddled in coats in cold schools, a college student started a fundraising campaign that has far exceeded its goal and the district is making emergency repairs.

Among those posting this week about the problem of inadequately-heated schools was former NFL player Aaron Maybin, a Baltimore native who now works at a city elementary school.

"This.Is.Unacceptable," Maybin wrote on in a tweet with a video of young children at a school. "It's really ridiculous the kind of environment we place our children into and expect them to get an education. I got two classes in one room, kids are freezing, Lights are off. No computers. We're doing our best but our kids don't deserve this."

The heating problems also got the attention of college student Samierra Jones, who says on her GoFundMe page that she is a graduate of Baltimore's public schools.

"How can you teach a child in these conditions?" Jones wrote, setting a goal Wednesday of raising $20,000. By Saturday afternoon, she had raised over $66,000, more than triple her goal.

Teachers also formally protested the conditions.

In a Wednesday letter to Baltimore schools CEO Sonja Brookins Santelises, the city's teachers union president said teachers were "forced to endure teaching in classrooms with dangerously low temperatures, instructing students who have been forced to try to learn bundled up in coats, hats and gloves."

The union president, Marietta English, said the "expectation that our members and the children that they teach endure bursting boilers, drafty windows, frigid temperatures in classrooms, and risk getting sick in these 'less than ideal' conditions, is utterly ridiculous."

A school district spokesperson, Edie House Foster, said in a statement this week, "Over the winter break, facilities staff monitored schools to check on heating systems, plumbing, and electricity. Numerous problems were identified and resolved. Unfortunately, with the extreme temperatures, new problems can emerge quickly."

"We have many schools with leaky windows and outdated heating systems that have a hard time keeping up," Foster said. "With extreme temperatures, we have the added challenge of freezing pipes and water main breaks."

Some schools were closed on Wednesday though others remained open.

All schools were then shuttered on Thursday due to snow, and they stayed closed Friday while the district assessed the infrastructure problems, The Baltimore Sun reported.

Baltimore Mayor Catherine Pugh on Friday called the conditions "unacceptable" and said in a letter to the City Council president that she ordered city engineers to help the schools and expedite repairs.

"We are working around the clock to connect essential resources, identify additional contractors and importantly, get our children back into the classroom as soon as possible," Pugh said.

On Twitter this morning Pugh said emergency maintenance is underway and Baltimore schools thanked those getting them ready for Monday.

Crews out in schools, getting us ready for Monday. Thanks to everyone on the team! https://t.co/c4PRtQ0AO1 — Baltimore Schools (@BaltCitySchools) January 6, 2018

Pugh also wrote in the Friday letter that "according to [Public Schools CEO] Dr. Santelises, there are many more problems than they are able to fix."

Pugh said $17 million has been allocated for maintenance issues for this year and that amount has been increased to $19 million for next year. ABC News' Meghan Keneally and Sarah Shales contributed to this story.