Five Palestinians were killed on Tuesday by Israeli artillery fire in eastern Gaza City, a spokesman for the emergency services said.
The army had no immediate comment on the shooting, which occurred shortly after four Qassam rockets were fired into southern Israel.
"Four rockets were fired into Israel from Gaza, three to the north and one in the south," an Israeli military spokeswoman said. They caused no damage or injuries.
The killings follow days of rising cross-border violence, which has ramped up tensions between Israel and Gaza's Islamist Hamas rulers and once again raised fears of a large-scale Israeli military invasion to stamp out rocket fire.