CHICAGO (CBS) – Bad blood between City Hall and the Chicago Teachers Union showed no sign of getting any better on Wednesday as the mayor and the union traded shots again over the push to get teachers to voluntarily accept a longer school day.

CBS 2 Chief Correspondent Jay Levine reports that the two sides can’t even agree on how many schools voted for and against the proposal.

It’s the difference between formal union-certified elections and individual school faculties that have informally told their union “no way” to a longer school day through informal votes at more than 100 schools.

The Mayor was asked Wednesday whether elections pitting teacher against teacher were a divisive influence in public schools.

“Let me tell you what’s divisive: not giving kids a chance at more reading, more math, more science,” Emanuel said. “So I don’t consider it divisive, what I consider it is taking a step in the right direction and people around the country now are looking at the city of Chicago and what we’re doing.”

“I think it’s very clear that the mayor is on a campaign to … pit people against one another. That’s what he does well. We all know who he is,” CTU President Karen Lewis said.

A group of teachers demonstrated outside Chicago Public Schools headquarters late Wednesday afternoon, protesting the Mayor’s tactics and claiming they’re being portrayed as villains for simply wanting to honor their current contract.

LISTEN: WBBM Newsradio’s Bob Roberts Reports

Lewis continued to charge that in one school – Nash Elementary on the West Side – a non-union bus driver was allowed to cast the deciding vote to extend the school day, even though the school principal claims the union’s own delegate certified the vote and outcome.

“I’m sure she had to say that, but that’s not what we were told,” Lewis said. “We are still trying to investigate that.”

Lewis also takes issue with the tally reported by the Mayor.

“Thirteen schools have adopted, four have not,” Emanuel said.

The union claimed that more than 100 schools have chosen not to adopt a longer school day. But CPS said that only 17 schools have formally voted, with the results, as the Mayor reported, 13 yes and 4 no.