Israel has shelled the northern Gaza Strip with artillery fire, wounding seven Palestinians, including two children. Palestinian medical sources said on Saturday: "Seven civilians, including a five-year-old child and a 13-year-old boy, were wounded by artillery fire west of Bait Hanun." Other medical sources told Aljazeera's correspondent in Gaza that only five Palestinians were wounded in the attack. They added that the wounded had been taken to hospitals in northern provinces for treatment. An Israeli military source had earlier said the shelling was in retaliation for rocket fire overnight on Friday, adding that four rockets coming from the area had exploded in Israeli territory but did not cause any casualties.Meanwhile, Palestinian security sources said the wife and the mother of a wanted al-Aqsa Martyrs Brigades local leader were arrested on Saturday at an Israeli checkpoint near the West Bank town of Nablus.