Two New York police officers were shot dead in Brooklyn, officials have said, in what local media called an apparent ambush.
The shootings came amid anger over the chokehold death of an unarmed black father-of-six by a white police officer, and a grand jury's decision not to press charges against him.
Local media said the assailant in yesterday's shooting had also died. It wasn't immediately clear if he had taken his own life.
"Our prayers are with our fellow #NYPD brothers who were executed in the line of duty today in #Brooklyn," the New York Police Department's 66th Precinct posted on its official Twitter page.
NYPD Captains Endowment Association president Roy Richter called the assault the "worst nightmare."
"Incredible sadness as we mourn for our brothers and their families," he added on Twitter.
Earlier, NYPD spokesman Sergeant Lee Jones told AFP that the two police officers were shot at the corner of Myrtle and Tompkins avenues in the 79th precinct.
"People are pretty shaken up," eyewitness Mike Isaacs told CNN.
"The mood is pretty freaked out, you know, a few people were saying it could be anyone."
The Post said the officers were shot as they wore their uniforms and sat in their marked police car while working overtime as part of a counterterrorism drill.
They were shot at point-blank range by a single gunman who approached their patrol car, it added.
Local media said the attacker fled on foot toward a subway station, where he was shot. The New York Post said he'd shot himself.
