Within hours of 10 Palestinian demonstrators being shot in Gaza, the latest victim was fatally wounded in Tulkarim on Wednesday night.
An Israeli military spokesman was not able to provide any details, other than that the dead man was armed.
Earlier, a member of al-Aqsa Martyrs' Brigades was killed during a fierce battle in the occupied West Bank city of Nablus.
Isam Arafat took a bullet in the chest in the Old City shortly after occupation troops invaded the area and surrounded two buildings, said Palestinian medical and security sources.
During the clashes, resistance fighters managed to detonate an explosive device near an occupation army vehicle, but it was not immediately clear whether there were any injuries or damage on the Israeli side, security sources said.
Five Palestinians were detained during the invasion, including one woman.
Earlier Israeli forces shot and killed a local leader of al-Aqsa Martyrs' Brigades during clashes in Jenin refugee camp in the northern West Bank, said Palestinian sources.
The group is an armed wing of Palestinian President Yasir Arafat's Fatah movement.
Israel's latest killings come a day after occupation soldiers killed two members of the brigades in separate incidents in the West Bank and amid a major ongoing assault in the occupied Gaza Strip refugee camp of Rafah.