Israel's first fatality in the war was also reported, with a man killed by rocket fire from Gaza near the Erez border crossing.
Gaza emergency services spokesman Ashraf al-Qudra said two Palestinians were killed in a car in southern Rafah and a third man was killed in central Johr al-Deek.
The three new deaths brought the toll in eight days of violence in Gaza to 197. Earlier, a 24-year-old man was killed in Zeitun, east of Gaza City, and a 77-year-old man was killed in the southern city of Khan Yunis.
They were the first fatalities since Israel renewed its air strikes after observing for six hours a ceasefire that Hamas snubbed.
The Egyptian-proposed ceasefire went into effect at 0600 GMT, but Hamas said it had not been consulted on the truce and would not halt fire without a full-fledged agreement involving Israeli concessions.
Before the 0600 GMT deadline, three people were killed in two separate air strikes on Khan Yunis, and two other men in the city succumbed to injuries sustained in earlier raids, Qudra said. Also in the south, a woman was killed in an earlier strike on Rafah.
Late Monday, the death toll rose above that of the previous major conflict between Israel and Hamas militants, an eight day confrontation in November 2012 which claimed the lives of 177 Palestinians and six Israelis.
One Israeli was killed on Tuesday evening by rocket fire from Gaza near the Erez border crossing. Four people have been seriously wounded.
The Gaza-based Palestinian Centre for Human Rights said on Sunday, when the Gaza toll stood at over 150, that three quarters of the dead were civilians.
And on Monday, a senior UN official said more than a quarter were children. The bloodiest day so far was Saturday when 56 Gazans were killed.
Israel began Operation Protective Edge before dawn on Tuesday in an attempt to halt cross-border rocket fire by militant groups.
Since then, over 960 rockets have hit Israel, while another 215 have been intercepted by its Iron Dome air defence system, the army said.