NEW YORK, May 19 (Reuters) - A prominent teachers' union filed suit Wednesday to halt the closure of 22 struggling New York City schools, accusing city education officials of breaching an agreement struck last year to keep many of the same schools open.

The New York City Department of Education failed to make promised changes at 15 of the 22 schools and instead opted to close them and seven other struggling schools, according to a lawsuit filed in the New York State Supreme Court, New York County.

Plaintiffs include the United Teachers Federation and the NAACP, both of whom were also plaintiffs in a similar suit in 2010. In that suit, the court found the city had violated state law in its school-closure process and blocked the city from shutting the schools down. An appellate division ruling upheld that decision.

In the current suit, the plaintiffs said the city again violated state law, as it did in 2010, by moving quickly to shutter, rather than improve, numerous schools across the city.

Many of the schools in question -- located in Manhattan, Brooklyn, the Bronx and Queens -- were designated by the New York State Education Department as low-performing and thus subject to more stringent review before they can be closed, the suit claims.

"Last year our lawsuit on closing schools demonstrated clearly that the city's Department of Education, much as it might want to be, is not above the law," said Michael Mulgrew, president of the UFT, which represents approximately 200,000 educators in New York City public schools. "But the DOE doesn't seem to have learned its lesson."

The suit is seeking to block the closures until the city follows the legal procedure outlined by the court ruling in 2010. The plaintiffs are also suing to block the "co-location" or expansion of 18 charter schools, which the plaintiffs claim would drain resources from nearby public schools. Co-location refers to the practice of charter schools and public schools sharing space in the same building.

New York City School Chancellor Dennis Walcott slammed the suit as "shameful."

"Every day that our students spend in a failing school does deeper and deeper damage to their prospects of succeeding in life," Walcott said in a statement. "That is why we will do everything we can to defeat this lawsuit and fight for what is in the best interest of our children."

Nevertheless, the city's Panel on Educational Policy voted in a series of contentious meetings in early 2011 to shutter the schools, citing poor performance and their perceived inability to improve their achievement records.

The suit is Michael Mulgrew et al v. The Board of Education of the City School District of the City of New York, New York State Supreme Court, New York County. The number was not yet available.

For the plaintiffs: Charles Moerdler, Alan Klinger and Ernst Rosenberger of Stroock & Stroock & Lavan.

For the DOE: Not immediately available.

(Reporting by Jessica Dye)