New York Police Department increased security at precincts across the city and directed that patrolling be done in pairs rather than by individual officers, said Officer Brian Magoolaghan, a department spokesman.
A memorandum issued to New York police on Friday urged officers to "maintain a heightened level of awareness" and stay vigilant, Magoolaghan said.
Police in the nation's capital also bolstered security around police stations and began patrolling in teams of two, said Dustin Sternbeck, director of communications, the USA Today reported.
A host of city police departments across the country directed their officers to patrol in pairs while on foot or in cars for greater security.
According to police and media reports, those cities included Chicago, Philadelphia, Seattle, Las Vegas and Cleveland. Identical steps were taken by law enforcement in the Los Angeles area at the county Sheriff's Department and the Glendale police.
Amid the rising police tensions, two officers were shot and wounded Friday in separate incidents. One occurred in Ballwin, Mo., outside St. Louis where an officer was shot three times in the neck during a traffic stop. The other was in Valdosta, Ga., where an officer came under fire responding to a report of damaged property at an apartment complex.