In the latest attacks on Friday, defeating blasts from the outskirts of Gaza City jolted people awake and led to screams of fear from people inside the city, the Associated Press reported.
Palestinians living in areas close to the Gaza-Israel border fled their homes in pickup trucks, on donkeys and by foot.
In the northern Gaza Strip, Rafat Tanani, his pregnant wife and four children, aged 7 and under, were killed after an Israeli warplane reduced their four-storey apartment building to rubble, residents said.
The tension between Israel and Gaza militants threatens to further escalate as the Israeli government is reportedly drafting a plan for a possible large-scale ground offensive in Gaza, similar to the one waged in 2014.
Power supplies may also be cut further as a result of the military action. Losses are much higher on the Palestinian side.
U.N. Secretary-General Antonio Guterres on Wednesday denounced the "indiscriminate" rocket launches from Gaza toward Israeli population centers while urging Israel to exercise "maximum restraint".
Israel unleashed its offensive on militants in Gaza after Hamas fired rockets at Jerusalem and Tel Aviv in retaliation for Israeli police clashes with Palestinians near al-Aqsa mosque in East Jerusalem during the Muslim fasting month of Ramadan.More news: Birthday Party Shooting in Colorado Leaves 7 Dead, Police Say
"There are now no IDF ground troops inside the Gaza Strip".
At the same time, Gaza militants fired more than 250 rockets toward Israel, injuring six civilians.
President Joe Biden defended the Israeli government's response to Palestinian rocket barrages, saying he has not seen a "significant overreaction".
Since then, Israel has attacked hundreds of targets in Gaza.
It added that fresh airstrikes had been carried out against what it called a "number of Hamas launch sites and observation posts in Gaza".
Early Friday morning saw some of the heaviest artillery fire and airstrikes on Gaza since hostilities began.
Footage appeared to show dozens of rockets raining down on the Palestinian enclave, however, the Israeli army later clarified that its troops had not entered the Gaza Strip as it had earlier stated, blaming an "internal communication" problem for the confusion.
Lt. Jonathan Conricus said the focus of Israel's attack on Gaza was the elaborate system of tunnels that Hamas has built over the years. Israel's forces destroyed "many kilometres" of the tunnels during the attack, it claimed.More news: India sees 403000 new virus cases, 4092 deaths in 24 hours
Israeli Defense Forces spokesperson Avichay Adraee told Anadolu Agency that he could not confirm the ground operation but could only say that an air and land attack has been launched on Gaza.
Israeli security forces have also been scrambled to contain deadly riots between Jews and Arabs, and projectiles have been fired on Israel from Lebanon.
On Thursday, Russian President Vladimir Putin spoke with United Nations chief Antonio Guterres, where Moscow said it was stated that the "primary task" was "to stop violent actions on both sides".
It was using its "intelligence collecting capabilities" to learn about any plans to carry out attacks or engage in violent clashes and "to locate, arrest, investigate and put the perpetrators on trial", it said in a statement.
The fighting in Gaza has spilled over into communal clashes inside Israel, where decades of pent-up grievances and nationalism have exploded into rampages by Arabs and Jews.
"A short while ago, three rockets were fired from Lebanon into the Mediterranean Sea off the coast of northern Israel", tweeted Israel Defense Forces (IDF). "Too many innocent civilians have already died".
Intercommunal violence, including beatings, stabbings, shooting and arson, has this week been reported across the country, from Beersheba in the southern Negev to Tiberias and Haifa in the north.
JERUSALEM - Israeli Justice Minister Benny Gantz has called on the chiefs of big social media platforms to quickly remove content from their sites that incites violence or spreads disinformation.More news: Man shot to death at Vancouver airport was subject of public warning