Four US police officers and four civilians were shot in Philadelphia, Pennsylvania and Fort Worth, Texas, authorities said.

In Philadelphia, sergeant Sylvia Young, 19, was ambushed late Friday night and shot a number of times in her left arm and protective vest, said Philadelphia Police Commissioner Richard Ross. Xinhua reported.

The suspect later wounded Ed Miller, a former police officer who is now a member of the security force at the University of Pennsylvania, Ross said.

During the police chase, a woman was killed and three other civilians were injured by the suspect, before he was cornered in an alley and fatally shot by the police.

Young and Miller were rushed to hospital and were in stable condition early Saturday, Ross said.

In another incident in Fort Worth, two police officers were responding to a suicide call at a house Friday night.

When they entered the house, a suspect inside the backyard shed began shooting, local media reported.

One officer was shot several times and in critical condition, while the suspect was later found dead by the police.