WASHINGTON (Reuters) - President Barack Obama said on Thursday he was granting 10 U.S. states exemptions from parts of the "No Child Left Behind" education law, a move that could prove popular in an election year with parents and teachers who have criticized the law.

"After waiting far too long for Congress to reform No Child Left Behind, my administration is giving states the opportunity to set higher, more honest standards in exchange for more flexibility," Obama said in a statement.

"Today, we're giving 10 states the green light to continue making reforms that are best for them," said Obama, who is scheduled to speak in more detail about the education law waivers at a White House event at 1:55 p.m. EST (1855 GMT).

The education law, a signature initiative passed under President George W. Bush, was aimed at holding public schools accountable for improving student performance. But it has been heavily criticized by many parents, teachers and state government officials.

The states to be granted waivers are Colorado, Florida, Georgia, Indiana, Kentucky, Massachusetts, Minnesota, New Jersey, Oklahoma, and Tennessee.

The administration is also pledging to work closely with New Mexico, another state that has made a formal request for a waiver.

Many U.S. states have complained about provisions of the law that tie federal education money to the ability of schools to meet the proficiency standards. State and local officials have said they want greater flexibility to set their own standards.

The decision to grant exemptions could help Obama politically as he campaigns for another term ahead of the November 6 U.S. presidential election.

The law's focus on testing students in math and language arts has drawn broad criticism from teachers and parents, who contend that schools often focus so intensively on those subjects, they slight science, social studies and the arts.

Education Secretary Arne Duncan recently echoed those concerns, writing that the emphasis on math and reading scores "as the primary measure of school performance has narrowed the curriculum."

Yet supporters of No Child Left Behind say it has proved invaluable in focusing attention on low-income, special-education and minority children.

Instead of aggregating scores across a grade level, schools must report scores for each demographic sub-group and demonstrate that all children are making progress.

Advocates for struggling children say waiving the law's requirements undermines a decade's worth of effort to bring students from all backgrounds up to par.

(Additional reporting by Stephanie Simon in Denver; Editing by Eric Beech)

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