Israeli troops, backed by armored vehicles and aircraft entered the area to the east of the southern city of Khan Yunis before dawn, and attacked a group of militants.
A gunman from the Islamic Jihad movement was killed, and four others, including another group member, were wounded in an air strike east of Khan Yunis.
An earlier air strike targeted 11 members of the Hamas group, which seized control over Gaza in June 2007. At least one person injured in the strike is in a critical condition.
Israeli aircraft carried out at least four air strikes on Wednesday.
Israel regularly conducts cross-border raids on the Gaza Strip to counteract so called standard terrorist threats, such as rocket attacks and terrorist raids.
