The United States is sending 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 team plans to visit polling stations and meet with Israeli and Palestinian officials.

The State Department says successful elections will require close cooperation between Israel and the Palestinians.

Earlier Tuesday, Israeli tanks fired shells in northern Gaza, killing seven Palestinians, six of whom were members of the same family.

The Israeli military says the tanks fired at militants who had fired mortars into a nearby Jewish settlement.  But witnesses say the victims were farmers and that militants had fled by the time the tank shells hit.