Barack Obama denounces killing of NYPD officers
US President Barack Obama has strongly condemned the killings of two New York City police officers shot by a man who then killed himself on Saturday.
Mr Obama said the officers would not be going home to their loved ones "and for that, there is no justification".
The two were killed while on patrol in Brooklyn. New York's police chief says they were "targeted for their uniform".
The gunman had posted anti-police messages online, amid continuing tensions over police tactics.
In a separate development, officials said a police officer was shot and killed in Florida early on Sunday.
They said a suspect was taken into custody, and more details would be unveiled at a news conference later in the day.
In a statement, President Obama said: "I unconditionally condemn today's murder of two police officers in New York City."
"Officers who serve and protect our communities risk their own safety for ours every single day and they deserve our respect and gratitude every single day," said Mr Obama, who is on holiday in Hawaii.
The gunman - named as Ismaaiyl Brinsley, 28 - was a black man while the two officers, Liu Wenjin and Raphael Ramos, were Asian and Hispanic respectively.
Before shooting them, Brinsley suggested on social media that he was planning to kill police in retaliation for the death of Eric Garner, a black man who died when white officers tried to arrest him for selling cigarettes in New York.
Earlier this month, a grand jury decided not to indict an officer over his death. Last month, another grand jury also cleared a white officer in the fatal shooting of Michael Brown, an unarmed black 18-year-old, in Ferguson, Missouri.
Both decisions triggered nationwide protests.
Commenting on Saturday's incident, New York City police commissioner Bill Bratton said the two officers had been shot at point blank range in their patrol car, with "no provocation".
"They were, quite simply, assassinated - targeted for their uniform and for the responsibility they embraced to keep the people of this city safe," Mr Bratton said.
After the shooting in the Bedford-Stuyvesant area, the gunman ran into a subway station where he killed himself as police closed in.
Mr Bratton also said Brinsley had wounded a former girlfriend earlier on Saturday in Baltimore, Maryland, and had made posts from her Instagram account.
"This may be my final post," said one that included an image of a silver handgun.
New York Mayor Bill de Blasio said anyone seeing postings indicating a threat to the police should report them.
The last fatal shooting of a New York police officer was in 2011.
The New York Times newspaper says Saturday's killing seemed to deepen a rift between Mr de Blasio and some rank-and-file officers who they regard as not supportive enough in the face of protests.
Video footage showed some officers turning their backs on the mayor as he walked into his news conference.
Patrick Lynch, who heads a leading police officers union, said: "There's blood on many hands tonight - those that incited violence on the street under the guise of protests", adding that "blood on the hands starts on the steps of City Hall, in the office of the mayor".
The Rev Al Sharpton, a prominent civil rights activist, said Mr Garner's family had had no connection to the gunman and he denounced the killing.
"Any use of the names of Eric Garner and Michael Brown in connection with any violence or killing of police, is reprehensible and against the pursuit of justice in both cases," Rev Sharpton said.