CHICAGO: Chicago teachers stayed away from public schools yesterday for a third day in a strike over Mayor Rahm Emanuel's demand for tough teacher evaluations that US education reform advocates see as crucial to fixing

urban schools.

With some 350,000 children from kindergarten to high school age out of school, the patience of their parents began to fray as hopes were dashed for a quick resolution to the biggest US labor strike in a year.

Fiery union president Karen Lewis, who has called Emanuel a "liar and a bully," said the two sides had agreed on only six of nearly 50 provisions of a new teacher contract.

An exasperated Chicago School Board President David Vitale

said that he would not be back to the negotiating table yesterday until the union made a comprehensive proposal to resolve the strike.

Lewis led the walk out on Monday of more than 29,000 teachers and support staff in the nation's third-largest school district, saying that the union would not agree to school reforms it considers misguided.

The dispute jolted the United States, where a weakened labor movement seldom stages strikes and even less frequently wins them. Organized labor has lost several fights in the last year including Wisconsin stripping public sector unions of most of their bargaining power, Indiana making union dues voluntary and

two California cities voting to pare pensions for unionized workers.

The strike in Barack Obama's home city has put the US president in a tough spot between his ally and former top White House aide Emanuel, and labor unions he needs to win the presidential election on Nov. 6.

Obama has said nothing in public about the dispute, allowing administration surrogates to urge the two sides to settle. "The president has said what is appropriate to be said, which is that it is a local issue," said Randi Weingarten, national president of the union that represents Chicago teachers. "It has national implication, but it has to be settled at the bargaining table."

Obama's own Education Department has championed some of the reforms Emanuel is seeking, and a win for the ambitious Chicago mayor would add momentum to the national school reform movement.

The first poll of Chicago voters since the strike showed 47 percent supporting the teachers union, 39 percent against the strike and the rest uncommitted, according to the Chicago Sun-Times newspaper. But that could change as the strike drags on and parents are forced to find childcare or stay away from

work for days.