A teenage Palestinian demonstrator has been killed in clashes with the Israeli army in the West Bank city of Hebron.Violence erupted during a demonstration against the ongoing Israeli offensive against Hamas militants in the Gaza Strip. Hamas had called on all Palestinians to observe another “day of anger” as the conflict entered its 21st day. Thousands of Palestinians took to the streets in support of the call (which was backed by the rival Fatah party of Palestinian President Mahmoud Abbas.) Fearing the Gaza crisis would spark violence in the occupied West Bank, Israel had imposed sweeping additional controls on movement and flooded Jerusalem’s Old City with armed security personnel during Muslim weekly prayers. In the West Bank city of Ramallah hundreds more Palestinians took part in a demonstration against the incursion into Gaza, some carrying images of Venezuelan President Hugo Chavez who broke off diplomatic relations with Israel on Wednesday. There were running street battles in East Jerusalem as riot police and border guards went to the aid of the driver of an Israeli car which was attacked by the demonstrators.