By Nidal al-Mughrabi JABALYA, Gaza, Nov 8 (Reuters) - Palestinian teenager Asma al-Athamna lies in a hospital bed, her body lacerated by shrapnel wounds, her eyes red from weeping. A few hours earlier, Israeli artillery shells crashed around Athamna's house, dismembering her mother and sister, and killing uncles and cousins. In all, 13 members of Athamna's extended family were killed in the shelling of the northern Gaza Strip town of Beit Hanoun, Palestinian officials said. "We were asleep and we were awakened by shells hitting the house of my uncle next door. Then the windows to our house were blasted away," said Athamna, 14, her voice shaking. "We fled the house only to be hunted outside. The shells killed my mother and sister and wounded all my siblings." As she spoke, doctors and nurses at the hospital in nearby Jabalya town tended to the wounded, many of them from the Athamna family. Downstairs, dozens of frantic Palestinians sought news of loved ones wounded in the shelling. Medics threw buckets of water into ambulances, trying to wash the blood away. Doctors gloves, covered in blood, lay on the ground. An Israeli military spokeswoman said it had fired artillery shells at northern Gaza in response to militant rocket launchings towards Israel. Israeli media reports, which the spokeswoman could not confirm, said an artillery battery had missed its target, a rocket-firing site, about a kilometre (0.5 mile) from Beit Hanoun. Residents said the Athamna family owned four of the seven houses that were hit. WOUNDED COUSIN Athamna, her mother and her sister managed to get out of their house when the shelling started. "People outside the house called on us to flee. We ran from the house into a narrow corridor. At least eight shells landed in the street," Athamna said. "We were afraid of death inside the house. But death took my mother and sister outside." Lying next to Athamna was her two-year-old cousin, Mallak al-Athamna. She had shrapnel wounds to the face. Doctors said both would live. The teenager's injured father was also in the hospital. Across Gaza, shops closed in protest at the attacks and to mourn the dead. Activists from the governing Hamas Islamist movement burned tyres and vowed revenge. Funerals will be held later on Wednesday in Beit Hanoun, the focus of Israel's biggest offensive in Gaza in a year. Israeli forces had withdrawn from the town on Tuesday after a week-long assault, designed to stop militants firing rockets, killed 52 militants and civilians, hospital officials and residents said.