Luai al-Saadi, leader of Islamic Jihad's military wing al-Quds Brigades in the West Bank, and Majid al-Ashqar, an al-Aqsa Martyrs Brigades member, were assassinated during an Israeli military operation in Tulkarim, Aljazeera's correspondent in Palestine reported on Monday.
The al-Aqsa Martyrs Brigades is linked to Palestinian President Mahmoud Abbas' Fatah party.
Israeli occupation forces were backed by about 15 armoured vehicles during the incursion into the eastern neighbourhood of Tulkarim city.
Other reports said Israeli forces had surrounded a house in the area when the shooting began, injuring one soldier.
Israeli forces removed the bodies from the scene, but have not released the names of those killed.
Six Palestinians were also detained during Monday's operation.
The Israeli army later imposed a curfew on Tulkarim, including the Nur al-Shams Palestinian refugee camp, Aljazeera learned.
Also in the West Bank, Israeli forces detained 26 Palestinians overnight as part of an ongoing wave of arrests in the occupied territory, military sources said on Monday.
The majority of those detained were members of another Palestinian resistance movement, Hamas, which has been the main target of the military operations.
The arrests were made in the Hebron, Bethlehem, Nablus and Tulkarim regions of the territory, the sources said.
The army was also continuing searches in Tulkarim after Israeli soldiers killed two Palestinians late on Sunday, who the military said were armed.