NEW YORK - New York Mayor Bill de Blasio faced the biggest crisis of his political career on Sunday after a gunman killed two police officers in an attack intended to avenge recent police killings of unarmed black men in the United States.
New York police officers turned their backs on de Blasio in protest during a news conference and their union said the mayor had blood on his hands after Saturday's shooting.
Police investigators have said the killings were the work of a 28-year-old black man with a long arrest record who may have had past mental troubles and who warned of his intentions on social media.
The gunman's posts on Instagram indicated he had been motivated by the deaths of 18-year-old Michael Brown and Eric Garner at the hands of police officers.
De Blasio was elected last year on a promise to advance civil rights after two decades of tough policing helped New York shed its reputation for violent crime.
He has been sympathetic to the protesters who poured into New York's streets after a grand jury declined earlier this month to indict the officer who killed Garner in a chokehold in July as he resisted arrest.
The mayor's stance has led to sometimes tense relations with the city's largest police union. Critics within the force view the mayor as not supportive enough at a time of public anger.
"Mayors tend not to do well when the police department and its officers are not happy," said New York political strategist Hank Sheinkopf, whose clients have included de Blasio's predecessor, Michael Bloomberg.
The deaths of Garner in New York and Brown in Ferguson, Missouri, led to sometimes violent protests across the United States. A grand jury also declined to charge the officer involved in Brown's death.
The cases provoked a bitter public debate about race and law enforcement that has drawn in President Barack Obama and his black attorney general, Eric Holder.
Leaders of recent anti-police protests, including longtime New York civil rights activist Reverend Al Sharpton, have condemned the officers' murder.
About 100 protesters, part of a group who recently met with de Blasio to call for police reforms, held a demonstration on Sunday night in Harlem. In contrast to usually boisterous protests critical of police, participants marched in silence bearing candles.
A candlelight vigil for the slain officers was also held in Brooklyn near the scene of the shooting.
Obama, briefed on Saturday about the police deaths while on vacation in Hawaii, called New York Police Commissioner William Bratton on Sunday to express condolences for the killing. Bratton heads the largest police department in the country.
'TENSION AND DIVISION'
New York's Roman Catholic cardinal, Timothy Dolan, warned of rising tensions during a Sunday service attended by de Blasio and Bratton.
"We worry about a city tempted to tension and division," Dolan said at St. Patrick's Cathedral.
Flags across the state flew at half staff and the 13-year-old son of one of the deceased officers bid his father good-bye in a Facebook post.