Palestinian witnesses said soldiers opened fire at a group of armed men in Tulkarim refugee camp, killing two and seriously wounding a third.
Aljazeera's correspondent said all three men were members of Izz al-Din al-Qassam Bridges.
Izz al-Din al-Qassam Brigades have vowed to increase attacks after Israel killed two prominent Hamas leaders in helicopter strikes in the Gaza Strip in the past two months.
Israeli military sources said occupation forces had to open fire first in case they were attacked.
A third Palestinian died of injuries sustained a few days ago in Diyar Abu Mishaal village near the West Bank city of Ram Allah, our correspondent added.
The deaths come as Israeli troops tighten security in case of an attack during its Independence Day holiday.
On Monday, soldiers killed a 15-year-old Palestinian in the village of Bait Lahiya in the Gaza Strip when they opened fire on a group of stone-throwers.
Occupation forces are responsible for killing more than three thousand Palestinians in over three years of violence.