The Chicago School Board voted Wednesday to shutter 49 elementary schools and one high school in the nation's third-largest school system despite demonstrations and community outrage over the closings.



Mayor Rahm Emanuel and Chicago Public Schools officials said the move is necessary to improve education and get the school district on better financial footing.



"The only consideration for us today is to do exactly what is right for the children,'' schools CEO Barbara Byrd-Bennett said before the board's vote.



But Chicago Teachers Union president Karen Lewis called the closings a "cowboy mentality" and said education "has been hijacked." She said Wednesday was a "day of mourning" for many schoolchildren who will be forced to cross gang boundaries in order to get to their new classrooms.



"Mayoral control is out of control," Lewis told reporters. She pledged a voter registration drive in an attempt to register 200,000 new voters before the 2015 municipal elections -- when Emanuel will be up for re-election -- and to raise funds to support candidates for mayor, city council and statewide office.



"We know that we may not win every seat we intend to target but with research, polling, money and people power we can win some of them,'' she said.



Emanuel noted there may be political consequences for the closures but paid them no mind, saying that taking no action would mean far greater consequences for students.



"I know this is incredibly difficult, but I firmly believe the most important thing we can do as a city is provide the next generation with a brighter future," he said in a written statement after the board's action. "More hard work lies ahead, but I am confident that together with teachers and principals, engaged parents and community support, our children will succeed."



Four schools escaped the closure list that was released in March. Chicago Board of Education vice president Jesse Ruiz confirmed to NBC Chicago hours before the vote that Byrd-Bennett had withdrawn her recommendation to close George Manierre Elementary School, Marcus Garvey Elementary School, Mahalia Jackson Elementary School and Leif Ericson Elementary Scholastic Academy.

The Chicago Teachers Union has said a single school closure is one too many and 50 or more would be catastrophic for the district, but teachers admitted the late move was a step in the right direction.

"It's a great start. We have 50 more to go," Chicago Teachers Union member Kristine Mayle said earlier Wednesday.

"There's an old expression," CTU Vice President Jesse Shakey said. "Don't put a knife in my back six inches, pull it out a couple and say you're doing a favor."

Other union members left for Springfield Wednesday morning to press lawmakers to pass legislation that would put a moratorium on school closings, and in Chicago, there was optimism that more schools could be saved.

"We saw at the last board meeting that there actually was some dissension for the first time," Mayle said. "We'd never seen that before in all these years we've been doing this. Hopefully when they actually got out to these schools they saw what was actually happening in these neighborhoods."



Chicago is among several major U.S. cities, including Philadelphia, Washington and Detroit to use mass school closures to reduce costs and offset declining enrollment. Detroit has closed more than 130 schools since 2005, including more than 40 in 2010 alone.



The school closings are the second major issue pitting Emanuel against the Chicago Teachers Union. The group's 26,000 members went on strike early in the school year, partly over the school district's demand for longer school days, idling students for a week.



More than 300 of the district's 681 schools were initially eyed for closure. That number was dwindled to 129 schools in February when Byrd-Bennett announced more specific criteria as to which schools might be affected to deal with what she called a "utilization crisis."



She's maintained the district has about 100,000 more seats than students at a time the district is facing a $1 billion deficit. Each closed school, she's said, would ultimately save the district between $500,000 and $800,000, saving the district $560 million over 10 years in capital costs and an additional $43 million per year in operating costs.



CTU officials have openly questioned those figures.

Byrd-Bennett: Closures Mean Additional Resources for Remaining Schools

Byrd-Bennett: Safety Trumps All Other Decisions

Byrd-Bennett on Potential School Closure Moratorium

Parent: School Closures Especially Difficult for Special Needs Kids



The Associated Press' Sara Burnett contributed to this report.