The two activists of the hardline Islamic Jihad group, which has been behind the most recent Palestinian attacks on Israeli targets, were hit as they were travelling in a vehicle near the Jabaliya refugee camp in the north of the territory, the medics said.
A total of 49 Palestinians and one Israeli soldier have been killed in Gaza since Israel launched its major offensive last Wednesday.
More than 200 people have been wounded, by the mission, rescue services in Gaza say.
Earlier Sunday, national security force member Hossam Obeid, 27, was killed by Israeli fire in the northern town of Beit Lahiya that wounded two others, medics said, adding that two other men, including a policeman, had died of their wounds.
Militant Mehdi Kamel al-Hamarine, 25, was also killed by shots to his stomach in the nearby city of Beit Hanun, which has borne the brunt of Israel's Operation Autumn Clouds.
The armed wing of the ruling Islamist movement Hamas confirmed that Mr Hamarine was one of its members.
Also in Beit Lahiya, Ammar Omar, 23, died of wounds sustained the day before, medics said. It is not clear whether he was a militant.
And a 32 year old policeman, Aatef al-Kahlut, died of wounds he received Saturday while in his home in Beit Hanun, medics said.
Three other people were wounded Sunday as the Israeli army blew up at least three houses in Beit Hanun, according to medics and witnesses.
Separately in the occupied West Bank, an 80 year old Palestinian woman, Fatma Zahan, died in a Bethlehem hospital, five days after being wounded by Israeli army fire, medics said.