The latest airstrike killed Samir Hamdan shortly after midday in an airstrike in Beit Hanoun, Gaza health ministry spokesman Ashraf al-Qidra said, while Hussein Muhesin, 19, died of wounds sustained in an airstrike on Gaza City.
Three children were injured in the strike.
Earlier, Layla Hasan al-Udat was killed in al-Maghazi refugee camp in central Gaza and Ashraf Zurub, 21, died from wounds sustained a day earlier in airstrikes.
Husam Ibrahim al-Najjar, 14, was killed in Sunday attacks in northern Gaza and 80-year-old Hijaziyya al-Hilou was killed in the Shujaiyya neighborhood of Gaza City when an Israeli missile hit the al-Hilou family home.
Medics said it was a miracle the rest of her family survived the attack.
Israeli warplanes intensified air raids overnight, targeting Hamas buildings in Gaza City and bombing a PA security services base in Rafah.
Three people, including an unidentified child, died Sunday from wounds sustained overnight and days earlier.
Ramziyya al- Abdul, 73, and Rami Abu Shanab, 25 died at al-Shifa Hospital in Gaza City of wounds they sustained two days ago in an Israeli airstrike on a house in Deir al-Balah.
Izz Addin al-Bulbul, Shadi Muhammad Zurub, 21, Bassam Zurub, 21, and Islamic Jihad fighter Muhannad Yousef Abu Dheir, 23, were all killed in airstrikes targeting Rafah.
Late Saturday, 18 Palestinians were killed in an Israeli airstrike on the Tuffah neighborhood that hit a house and mosque, emergency services spokesman Ashraf al-Qidra said, making it the single most deadly attack since Israel's assault began.
Another 35 were wounded in the same strike, and three more people were killed in southern Gaza's Rafah that also injured five people, Qidra added.
Among the wounded was police chief Tayseer al-Batsh, officials said.
OCHA said Saturday that 70 percent of Palestinian fatalities are civilians, of whom 30 percent are children.
Army warns north Gaza
In a sign of a likely further escalation, Israel dropped leaflets over northern Gaza, urging residents of the town of Beit Lahiya in particular to leave their homes "for their own safety".
"Civilians are requested to evacuate their residences immediately and move by 12 p.m. today," the leaflets said, naming locations which would prove to be most dangerous.
A UN official said that some 4,000 Palestinians have already fled their homes and sought refuge in UN facilities.
On Saturday, UNRWA official Robert Turner said that the UN refugee agency could house over 50,000 Palestinians refugees if a ground invasion took place.
Israel has warned that preparations are under way for a possible ground incursion, with tanks and artillery massed along the border and some 33,000 reservists mobilised out of 40,000 approved by the cabinet.
Israeli hardline Foreign Minister Avigdor Lieberman has said he expects a political decision on a possible ground operation to be taken by Sunday.