© Reuters/John GressMembers of the Chicago Teachers Union carry placards outside the Benito Juarez High School on the fifth day of their strike in Chicago September 14, 2012.
The Chicago Teachers Union and the nation's third largest school district reached an "agreement in principle" to end a five-day strike over Mayor Rahm Emanuel's demand for education reforms, the school district said on Friday, raising hopes that teachers would be back in class on Monday.

"CPS (Chicago Public Schools) and CTU (Chicago Teachers Union) have come to an agreement in principle," the school district said in a message posted on Twitter.

Chicago School Board President David Vitale said the framework deal should allow students to be back in school on Monday morning.

More than 350,000 Chicago students marked a week off classes on Friday after some 29,000 Chicago teachers and support staff walked off the job over the education reforms.

The union's house of delegates, a larger consultative body than the negotiating team, was meeting on Friday afternoon to discuss the state of negotiations. It was not clear if they would vote on the agreement in principle.

The school district said the framework would first have to be approved by the union's delegates and then go to the full membership before it was final.

The teachers walked out on Monday in the first Chicago Teachers Union strike since 1987. It was the largest strike in the United States in a year and has galvanized the labor movement and exposed a rift within the Democratic Party over reforms of urban schools.

Parents of kindergarten, elementary and high school students were forced to find alternative child care, keep their children at home or take them to nearly 150 centers around Chicago set up by the city to provide breakfast, lunch and supervision.

Striking teachers resumed picketing around schools staffed by principals and volunteers. More than 80 percent of Chicago public school students qualify for free school lunches because they come from low-income families. Crime and gang violence plague many neighborhoods on the city's poorer south and west sides.

Kenwood Academy high school senior Sandy Danard, 17, who marched to support teachers, said she risked missing the application deadlines for some colleges because she could not get a paper transcript from her school.

"The counselors aren't in school," she said. "It's really stressful on the seniors, and in the end when the strike finally ends, we have to rush."

Extracurricular activities such as high school sports and the arts also have been suspended.

National Spotlight

The teachers' strike is unusual in the United States where unions have been severely weakened by state and local laws constraining their power, and union membership has fallen in a service economy. There were only 19 strikes of 1,000 workers or more in all of 2011, according to government figures.

Teachers revolted when Emanuel, with support from a national school reform movement largely financed by wealthy philanthropists, tried to pin much of teacher evaluations to students' performance on standardized tests in areas such as reading and math.

Using student test scores to rate teachers is in vogue nationally, championed by President Barack Obama's Education Department to raise standards and improve schools. Obama's education secretary, Arne Duncan, once led Chicago schools.

The union argues that the policy forces them to teach to the test and narrows the curriculum. Chicago teachers also said they should not be evaluated on factors outside their control such as poverty and crime, which their students endure in some neighborhoods.

Karen Lewis, the fiery former high school chemistry teacher who leads the union, shrewdly built support among parents and teachers in Chicago's inner-city communities for two years before calling the strike. The community organizing resulted in strong backing for the strike as well as enthusiastic rallies and picketing.

Emanuel has retreated on his teacher evaluation demands, agreeing to phase in the new standards and lowering the percentage weighting of standardized tests.

Emanuel faces financial as well as political pressures.

The school district has offered average wage increases of 16 percent over four years plus some benefit improvements. It is not clear how Emanuel will pay for those since the district faces a $665 million budget deficit this year, has drained financial reserves and levied property taxes to the legal limit.

The high-profile labor clash in Obama's home city has been awkward for the president. Emanuel is Obama's former top White House aide and a key fundraiser for the president's re-election campaign. Unions are a key constituency of the Democratic Party and will be important in getting out the vote on November 6.

Additional reporting by Peter Bohan, Karen Pierog, Nick Carey and Mary Wisniewski; Writing by Greg McCune; editing by Christopher Wilson