The New York City police officers killed in what Commissioner William Bratton described as an assassination were Rafael Ramos and Wenjian Liu.
Liu, 32, had been on the force for seven years. He got married two months ago, Bratton said at a news conference.
Ramos, 40, joined the department in January 2012. He had previously worked as a school safety agent, which falls under the agency.
He was married and had a 13-year-old son.
"Two of New York's finest were shot and killed with no warning, no provocation," Bratton said at a news conference. "They were quite simply assassinated and targeted for their uniform and the responsibility they embraced to keep the people of this city safe."
While the officers worked out of a different police precinct, they were assigned to the Brooklyn neighborhood as part of a critical response unit because of an increase in shootings in a nearby housing complex, Bratton said.
Liu and Ramos were stationed outside the complex, sitting in their marked squad car when Ismaaiyl Brinsley, 28, approached them at 2:47 p.m. and fired through the passenger-side window.
He struck both officers in the head, Bratton said. Ramos was sitting in the driver's seat. Liu was on the passenger side.
"Officer Liu, and Officer Ramos never had the opportunity to draw their weapons and may never have actually seen the assailant or murderer," Bratton said.
Brinsley killed himself not long after the ambush on a nearby subway platform as he was pursued by police. He had shot his ex-girlfriend earlier Saturday in her apartment in suburban Baltimore, Bratton said.
She underwent surgery and was expected to survive.
"This is not the first time the department has seen violence," Bratton said, noting that partners have been killed together seven times since 1972 — "often in senseless, mindless assassinations without warning.
"Our officers know this from memorial walls in precincts and at headquarters," the commissioner added. "They hear it from the stories they hand down.
"We will forget that mission," Bratton said. "We will never forget the two young men who lost their lives today."
William J. Bratton was the Boston (MA) police commissioner, the Boston Metropolitan Police superintendent, the Los Angeles (CA) Police Department chief, is the New York City Police Department commissioner, and a member of the Homeland Security Advisory Council.