(Adds response from Mayor Bill de Blasio)
By Jonathan Allen
NEW YORK, Aug 26 (Reuters) - A New York City police union leader on Tuesday castigated Mayor Bill de Blasio and his bid to host the 2016 Democratic National Convention, saying the city was losing ground in the fight against crime since he took office in January.
Ed Mullins, the president of the Sergeants Benevolent Association, leveled the criticism of the mayor in an open letter published as a full-page advertisement in The New York Times and in other outlets, as he called the police force "understaffed, overworked and underpaid."
The mayor dismissed the letter as "fear mongering" and an effort "to advance the union's position in contract negotiations."
The exchange was the latest evidence of the strained relationship between the mayor and the city's two largest police unions in the wake of an unarmed man's death during an arrest last month.
Mullins urged the convention's organizers to look elsewhere, saying de Blasio, the city's most liberal mayor in a generation, was making a scapegoat of the New York Police Department and allowing crime to rise.
"Mayor de Blasio has not earned the right to play host to such an important event," Mullins wrote in his letter. "The great officers of the NYPD are not pawns to be moved around a political chessboard by the Mayor."
He said de Blasio was taking the city back to the high-crime days of the 1980s, pointing to a recent increase in shootings in the city.
De Blasio, speaking at a press conference on Tuesday, said there have been 27 fewer murders in the city so far this year compared with the same period last year, and that the overall crime rate has reduced slightly.
"The NYPD should be very, very proud of that fact," de Blasio told reporters, according to transcript provided by his office. "So if any union wants to try to better their economic position, that is certainly their right, but do it based on the facts."
De Blasio took office after promising to mend frayed relations between the police and New Yorkers, especially black and Latino citizens who, according to a federal judge, had been disproportionately targeted for stops and frisks.
The death of Eric Garner, whose final moments begging for breath as a police officer gripped him around the neck were recorded on bystanders' smartphones, is the first major test of the mayor's promise.
Police say Garner was resisting arrest for peddling untaxed cigarettes on the sidewalk on Staten Island.
De Blasio has tried to strike a balance between assuaging New Yorkers who were outraged by the videos of Garner without alienating his police officers.
The city's two main police unions say the mayor is not doing enough to tell New Yorkers that policing is a dangerous job that is only made harder when people resist arrest.
The Democratic National Committee, which sent a team earlier this month to examine the Brooklyn venue proposed by the mayor for the 2016 convention, declined to comment. (Editing by Frank McGurty, Andrea Ricci and Leslie Adler)