Muhammad Sukha, 18, was shot dead on Friday in the casbah of the old city of Nablus, where the army has been carrying out what it called search operations since Thursday.
Palestinian medics and security sources said Sukha had been standing on the roof of a mosque and had thrown rocks at soldiers below, who then shot him in the stomach and shoulder.
Israeli military sources said troops had fired at him after spotting him on the roof, aiming to throw a gas canister at
The occupation forces sealed off the city for the second day, imposed a curfew and carried out a search campaign hunting for activists from Fatah's al-Aqsa Martyrs Brigades.
Israeli forces advanced into Nablus on Wednesday evening with 25 armoured vehicles backed by bulldozers and sealed off parts of the old city with barbed wires.
Palestinians in the affected areas have been confined to their homes.
Also on Friday, Israeli occupation forces seized Mahmud Samir Shahada, a resistance fighter from al-Aqsa Martyrs' Brigades in Ram Allah.
Palestinian children pick through
rubble of Bassam Abu Bakar's home
"Shahada's father said the occupation forces stormed Shahada's office in the city at dawn after blowing up its entrances. The occupation forces also raided a number of houses and kidnapped his son (Mahmud)", said Aljazeera's correspondent.
The troops also dynamited the house of Bassam Abu Bakar, a leader of Islamic Jihad's al-Quds Brigades whom it arrested a month ago.
The blast caused massive damage to two other neighbouring homes.