Israel has killed at least 27 Palestinians in the north and central areas of the Gaza Strip on Friday.
Some Palestinians displaced by the Israeli assault on Gaza said they feared their temporary beachside camp would be inundated by high waves.
According to Palestinian health officials, shelling by Israeli tanks killed eight people and wounded several others in the Nuseirat refugee camp in the central area of Gaza, and six others were killed in an airstrike on a house in Gaza City.
In the northern town of Beit Hanoun, an Israeli strike on a car killed and wounded several Palestinians, reports Reuters.
It was not clear how many of the casualties were combatants and how many were civilians.
In the southern city of Rafah, where the Israeli army has been operating since May, tanks advanced further to the northwest area backed by aircraft, residents said.
They also reported heavy fire and explosions echoing in the eastern areas of the city, where Israeli forces blew up several houses, according to residents and Hamas media.
"Our fighters are engaged in fierce gun battles against Israeli forces, who advanced into Tanour neighbourhood in Rafah," Hamas armed wing said in a statement.
The Israeli military has said that forces operating in Rafah have in the past weeks killed hundreds of Palestinian militants, located tunnels and explosives and destroyed military infrastructure.
Israel's demand to keep control of the southern border line between Rafah and Egypt has been the focus of an international effort to conclude a ceasefire deal between Israel and Hamas.
The United States and mediators Qatar and Egypt have for months attempted to secure a truce but have failed to bring Israel and Hamas to a final agreement.
Two obstacles have been especially difficult: Israel's demand that it keep forces in the Philadelphi corridor between Gaza and Egypt, and the specifics of an exchange of Israeli hostages for Palestinian prisoners held by Israel. Reuters