The Israeli army says Palestinian militants fired two homemade rockets into an army base near the Gaza border Wednesday, wounding 12 people, many of them soldiers.
The army said two other rockets landed earlier near the southern Israeli town of Sderot, but did not cause any casualties.
Palestinian militants in northern Gaza have stepped up rocket fire in recent weeks, prompting the Israeli army to launch new operations in the area to halt such attacks.
Meanwhile, the United States is preparing to send an official observer mission to Sunday's Palestinian election.
The State Department says the delegation will be led by Senators John Sununu and Joseph Biden and will include prominent Palestinian-Americans.
The State Department says successful elections will require close cooperation between Israel and the Palestinians.
Some information for this report provided by AFP and Reuters.