In the central Florida city of Kissimmee- close to the Walt Disney World Resort and other amusement parks- Officer Matthew Baxter was killed and Sergeant Sam Howard was left in "grave critical condition and the prognosis does not look good," police chief Jeff O'Dell said at a news conference early Saturday.
The officers had been checking on suspicious people in an area known for drug activity around 9:30 pm Friday (0130 GMT Saturday). Five minutes later, authorities received a call that officers had been shot.
First responders found the officers "gravely wounded" in the road, O'Dell said.
"My thoughts and prayers are with the @KissimmeePolice and their loved ones. We are with you!" President Trump, a staunch supporter of US law enforcement, tweeted early Saturday.
In the northern Florida city of Jacksonville, sheriff's officers responding to an attempted suicide call late Friday were confronted by a suspect firing a high-powered rifle, Director Mike Bruno told a news conference.
And two Pennsylvania state troopers were shot Friday night, the agency said.
"Two state troopers shot and [the] suspect is deceased," Pennsylvania State Police spokeswoman Melinda Bondarenka told ABC News. "We are not releasing any more details at this time."
Both troopers are expected to survive, ABC said of the shooting in the community of Fairchance, about 60 miles (97 kilometers) south of Pittsburgh.