TRENTON, N.J. (AP) -- New Jersey's statewide police union issued an email alert to the group's 33,000 members Sunday warning them to take extra caution after two NYPD officers were murdered.

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New Jersey State PBA Executive Vice President Marc Kovar said in the email that all members and officers should take extra caution and change up routines in the coming weeks, citing heightened hostility from nationwide protests that he says has led to a "fever pitch of anti-police sentiment."

"This open hostility has created more tense encounters with officers even on routine incidents such as motor vehicle stops," Kovar said. "The State PBA is advising officers to be alert for any interaction where a person may be looking for a confrontation."

New York police say 28-year-old Ismaaiyl Brinsley killed two officers Saturday after vowing online to shoot two officers in retaliation for the police chokehold death of Eric Garner. Another police officer was shot and killed in Florida Sunday morning.

Police said Brinsley approached the passenger window of a marked police car and opened fire, striking Officers Rafael Ramos and Wenjian Liu in the head. Brinsley was black; the officers were Asian and Hispanic, police said.

Kovar said officers need to be vigilant for potential ambushes and should "remain vigilant and avoid complacency."

He also suggests that officers change up routines, including meal breaks, and wait for backup for any calls that appear out of the ordinary.

In Newark, Police Director Eugene Venable said that no single officer units will patrol the city's streets in the wake of the shootings.

"We want our officers to continue to do their jobs and protect our citizens but we must first ensure that their personal safety is not unreasonably at risk," he said.

State Police spokesman Capt. Stephen Jones said that there are no known specific threats against New Jersey police officers.

There were two incidents of law-enforcement officers forced to fire their weapons between Saturday night and Sunday morning.

On Saturday night, an off-duty corrections officer exchanged gunfire with an armed robber in a clothing store in Newark. And on Sunday morning, a Belleville police officer fired at two armed robbery suspects who investigators said tried to ram him with their car.

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