Israeli soldiers on the Israeli side of the border with the Gaza Strip. (AFP/File Menahem Kahana)
Medical sources told Ma'an that Ahmad al-Harbawi, Abed al-Wahidi, and Hussam Dawla were shot and killed during the clashes east of the al-Shujaiyeh neighborhood east of Gaza City.
At least 19 other Palestinians were injured.
An Israeli army spokesperson told Ma'an that 200 Palestinians approached the security fence and hurled rocks and rolled burning tires at Israeli forces.
Israeli forces responded with live fire towards the "main instigators," she said, confirming five direct hits.
The deaths in Gaza come amid renewed violence in the occupied West Bank and East Jerusalem on Friday.
In the Israeli city of Dimona, an Israeli teenager stabbed four Palestinian Bedouins who worked for the local municipality, seriously injuring two.
A Palestinian was shot and killed in the illegal settlement of Kiryat Arba after attempting to stab an Israeli border officer, police said, while a Palestinian woman was also shot in Afula after allegedly attempting to stab an Israeli security guard.
Tensions had been mounting steadily for weeks across the occupied Palestinian territory due to Israeli restrictions on Palestinians seeking to enter the Al-Aqsa Mosque compound in East Jerusalem.
At least 900 Palestinians have been injured in seven consecutive days of demonstrations and clashes in the occupied West Bank and East Jerusalem, at least 60 with live fire, medics say.