The Israeli military renewed its campaign in the Gaza Strip as fresh rocket attacks by Gaza militants targeted Israel on the third day since an Egyptian-led temporary cease-fire collapsed.
The renewed exchanges have dashed hopes for a lasting truce after a month-long war that has already killed over 2,000 people.
Israeli airstrikes hit more than 20 terror targets in Gaza between Thursday and Friday in response to projectile attacks from Gaza the day before, a military spokeswoman confirmed to The Jerusalem Post.
Earlier this week, Hamas rejected an Egyptian truce proposal under which Israel would gradually ease its blockade of Gaza, without giving specific commitments.
A quick resumption of indirect talks between Israel and Hamas in Cairo seems unlikely, particularly after Israel killed three top Hamas military leaders in an airstrike Thursday.
Senior Hamas political leader Ismail Haniyeh said late Thursday that his group would not budge from its demands.
"We will not accept anything less than an end to the (Israeli) aggression and an end to the blockade," Haniyeh said in a statement posted by the Hamas-affiliated Al Rai news service. "Anyone involved in cease-fire efforts must understand that our people will not accept anything less than this."
Since Israel-Hamas fighting erupted on July 8, at least 2,086 Palestinians were killed, according to Gaza health official Ashraf al-Kidra.
On the Israeli side, 67 people have been killed in the past six weeks, including 64 soldiers, two civilians and a Thai worker.
One of Friday's airstrikes hit a livestock farm where two workers were killed, al-Kidra said. Three Palestinians were wounded in that strike.
The Israeli military said its strikes targeted concealed rocket launchers and weapons sites.
Israel said the three Hamas senior figures killed on Thursday had played a key role in expanding the militants' military capabilities in recent years, including digging attack tunnels leading to Israel, training fighters and smuggling weapons to Gaza. One of the trio also played a role in the capture of Israeli soldier Gilad Schalit in 2006. After being held captive in Gaza for more than five years, Schalit was exchanged for more than 1,000 Palestinian prisoners in 2011.
Israel says the Gaza blockade is needed to prevent Hamas and other militant groups from getting weapons. The restrictions prevent most Gazans from traveling outside the crowded coastal strip and bar most exports.
The Associated Press contributed to this report.