According to AFP, Palestinian hospital officials said six people died in a single strike on a group of people.
Earlier, Reuters quoted Palestinian medics as saying an Israeli tank shell had killed seven Palestinians including the three-year-old girl, but later said the death toll included an earlier air strike that killed two militants, including one from the ruling Islamist Hamas group.
The Israeli army confirmed the air strike, but said the latest attack in the town of Jabalya was an additional air strike, not a tank shell, launched against a group of militants who had fired an anti-tank missile at them.
Palestinian witnesses said the army targeted a crowd of Palestinians that had gathered to watch Israeli forces in the area.
They said three militants from a Hamas-led security force were among the five killed in the second strike but did not confirm if they had attacked the Israeli troops.
Three more Palestinians were wounded in the latest attack.
Several Palestinians were also wounded in two other raids. One struck a Gaza City building used by a controversial paramilitary force set up by the Hamas-led government, the other a house in the Gaza-Egypt border town of Rafah that had already been hit on Tuesday.
In all, several dozen people were injured in the raids, hospital officials said.
Israeli tanks in northern Gaza
Earlier, about 50 Israeli tanks moved back into northern Gaza.
Israeli troops took over rooftops of several houses in northern Gaza, residents said, and Israeli aircraft blasted several houses of Hamas and Islamic Jihad activists after warning the people to leave.
In another tactic, the Palestinian phone company said more than 1,000 residents of the southern Gaza city of Khan Younis received recorded messages from Israel, warning them not to hide weapons or shield militants.
Yesterday, a Palestinian boy was killed and his father and sister wounded near Khan Younis. Palestinians blamed Israeli gunfire, but Israel denied that.
The army said the only shooting incident at that time was near the Kissufim crossing five kilometres away, when troops fired at a group of people after they set off an explosive device next to the
border.
However, they did not hit them, the army said.
Hospital officials said the 12-year old boy, his 16-year-old sister and their father were shot after they stumbled on an undercover army unit.
The military said no Israeli forces were operating in the Khan Younis area.
West Bank building surrounded
In the West Bank about 20 Israeli jeeps entered the city of Ramallah last night and surrounded a building there, Palestinian security officials said.
The officials said the Israeli army had warned Palestinian security officials to keep their patrols off the streets because an operation to arrest wanted militants was underway.
The army confirmed that it was conducting an operation in Ramallah.
According to an AFP count, a total of 124 Palestinians and one Israeli soldier have died in the operations launched by Israel on June 28 in the Gaza Strip to recover an Israeli soldier captured by Palestinian militants and end the firing of rockets at Israeli territory.