LOS ANGELES (KABC) -- Los Angeles teachers are casting their votes on whether or not to possibly go on strike.The vote is actually not to go on strike, but to authorize one. It's a significant step in the ongoing dispute over a new contract for Los Angeles Unified School District teachers.United Teachers Los Angeles, which has about 33,000 members is demanding a 6.5 percent pay raise and reduced class sizes, among other things.Union officials say they've been at an impasse with the district in negotiations since late last month. They are demanding the district head back to the negotiating table before the end of the month with a state mediator, to help the two sides overcome hurdles preventing them from reaching a contract agreement.Union officials say members have been without a contract for well over a year and been without a pay increase for years as well. They say a 2 percent pay raise offered by the district is simply not good enough.The LAUSD Board of Education earlier this week issued a statement opposing a strike: "The Board of Education stands with students, their families and employees to ensure learning and safety comes first in L.A. Unified. There is currently an effort to call for a strike that pits adults versus adults when students and their families will bear the brunt of a strike action. For this reason, we, the Board of Education do not support a strike."