Israel acknowledged targeting the men, claiming they had ties to militants.
The strikes came yesterday on the seventh day of Israel's offensive against Gaza's Hamas rulers.
A number of journalists have been killed over the years while covering fighting between the Jewish state and the Palestinian militant group, but not in targeted strikes Israel acknowledged.
Two of those killed were cameramen working for Al Aqsa TV, the centerpiece of a growing Hamas media empire, said station head Mohammed Thouraya.
The two were driving in a car with press markings in Gaza City on Tuesday afternoon, shortly after wrapping up an assignment at the city's Shifa Hospital, Thouraya added.
The station said the car was hit by a missile, broadcasting the aftermath with the vehicle consumed by flames.
Thouraya said the bodies of the two, Mohammed al-Koumi and Hussam Salam, were badly burned.
Later yesterday, another Israeli missile killed an employee for Al Quds Educational Radio, a private station, said Ashraf al-Kidra, a Gaza health official.
Mohammed Abu Eisha died when his car was hit in the central Gaza town of Deir el-Balah, al-Kidra said.
Avital Leibovich, an Israeli military spokeswoman, said a preliminary investigation showed all three were Hamas operatives, but he would not elaborate.
Israel has struck a wide range of Hamas-linked targets during its offensive, including rocket launching sites and the homes of suspected activists, killing more than 120 people.
Asked whether Israel had widened it range of targets to include journalists working for media run by Hamas or other militant groups, Leibovich said: "The targets are people who have relevance to terror activity."
Thouraya denied that the two employees killed yesterday were linked to violence.
"Our crew were fighters, but they were not fighting with weapons," he said. "They were fighting with their cameras. They were on the battlefield to defend the people by filming the awful crimes (of the Israeli offensive) and broadcasting them to the world."
Gaza City: Israeli airstrikes killed three Palestinian journalists in their cars, a Gaza health official and the head of the Hamas-run Al Aqsa TV said.
First Published: Wednesday, November 21, 2012, 15:10