Two were killed in Qabatya village, near the northern city of Jenin, and the others in a Nablus refugee camp.
Mohammed Zakarneh, 18, from the Islamic Jihad faction, was killed and the house where he had been sheltering in Qabatya partially destroyed by army bulldozers, the Palestinian sources said.
An army spokesman said Israeli troops fired on militants who were allegedly setting up explosive devices, hitting one of the "armed men".
A few hours later, 24-year-old Hani Kmeil was also shot and killed by Israeli troops in Qabatya. Palestinian security sources said he was fatally wounded while throwing stones at soldiers.
An army spokeswoman said a second Palestinian was killed after forces used rubber bullets to disperse "heavy riots" that broke out in Qabatya. According to intelligence, the dead man had been "wanted" by the military.
A third Palestinian, 16-year-old Ezzedine Smadi, was also "very seriously wounded" after throwing stones, medical and security sources told AFP.
Meanwhile, Adel Abu al-Rish, 23, from the radical Al-Aqsa Martyrs Brigades, and Firas Abu al-Rish, a member of the Fatah party of Palestinian president Mahmud Abbas, were shot dead by Israeli special forces in the refugee camp.
The two relatives died when the forces opened fire at a Palestinian car, killing them, the local security and medical sources said.
An Israeli military source said special forces arrived to arrest a wanted Fatah operative, who was identified as armed and in a car.
"Forces fired at the wanted armed man and apparently both he and the driver was killed," the source told AFP.
The latest deaths bring to 5,438 the number of people killed since the start of the second Palestinian uprising in September 2000, the vast majority of them Palestinians, according to an AFP count.

Copyright AFP (Agence France-Presse), 2006