Three Palestinians, including a 13-year-old boy and a woman, were killed during an Israeli operation east of the Jabaliya refugee camp near Gaza city.
The clashes took place as U.S. President George Bush landed in Israel, his first stop on a six-day Middle East tour. Bush will take part in the country's 60th anniversary celebrations, and will meet with President Shimon Peres and Prime Minister Ehud Olmert.
Earlier on Wednesday two airstrikes on the western outskirts of Khan Younis killed two people and also left two others injured. Both the dead and injured were identified as militants from the radical Islamic group Hamas, which took control of Gaza last June.
According to witnesses, Israeli troops supported by several armed vehicles entered Khan Younis at dawn and are currently involved in ground operations against Palestinian militants.
Israeli Defense Forces frequently raid southern Gaza in an attempt to stop cross-border attacks by Hamas militants.
