Aljazeera's correspondent in Jenin said 15 military vehicles raided the town on Friday morning and imposed a curfew.
Eyewitnesses said Israeli forces launched sweeping raids on the outskirts of Jenin while Apache helicopters hovered over the area.
The raid comes a day after six Palestinians, including a three-year-old girl, were killed in a bloody day of Israeli violence in the occupied territories.
Occupation soldier killed
Israeli forces invaded al-Bureij refugee camp in Gaza early on Thursday, killing three Palestinians and a Hamas member.
An Israeli soldier was also killed and six were injured in clashes at the camp after helicopters launched an air strike targeting resistance fighters.
Meanwhile, in Hebron on Thursday, Ziyad al-Shuweiki, leader of the military wing of Islamic Jihad in Hebron and Abd al-Rahim al-Quaiq, his deputy, were killed when Israeli forces surrounded a house in the city.
And in another incident in Rafah, in the south Gaza strip, one Palestinian was killed during another Israeli invasion.
Israeli forces also arrested seven people in Jenin, including two foreign female volunteers, as they attempted to provide Palestinian families held by Israeli forces with food.