Mayor Bloomberg yesterday blasted Bronx legislators who rejected a $310 million retail development at Kingsbridge Armory, saying they undercut their own constituents who are suffering under the highest unemployment rate in the state.

“It’s sad,” said Bloomberg. “We desperately needed those good-paying jobs that were going to be there.”

State Labor Department statistics show that the unemployment rate in The Bronx in October was 13.4 percent, highest of any county.

Taking the lead from Bronx legislators, the City Council on Monday voted 45-1 to reject the mayor’s plan to convert the armory into a new retail center.

City Councilman Joel Rivera (D-Bronx) argued there wouldn’t have been much, if any, of a net jobs gain because the new retail complex would have cut into business on nearby Fordham Road.

“You would gain jobs on one side, and lose jobs on the other side,” he said.