Two Palestinian children, a brother and sister aged eight and six years, have died in an explosion in the town of Beit Hanoun in the northern Gaza Strip.
Eight other people, including children, were wounded in the blast.
Witnesses and medics in the Gaza Strip said that a shell or mortar they were playing with exploded.
But another report said that the explosion was caused by a rocket fired by Palestinian militants that had come to ground inside Gaza.
This is not an unusual occurrence.