Hamas vowed on Thursday that Israel "will pay the price" for killing three commanders of the Al-Qassam Brigades, the Islamist movement's military wing.
A pre-dawn Israeli air strike in southern Gaza killed the three senior commanders, identified as Mohammed Abu Shamala, Raed Al-Atar and Mohamed Barhum.
Hamas spokesman Sami Abu Zuhri said that the assassination of the men was “an Israeli crime,” that will not "weaken the resistance or break the Palestinian people's determination," reported Egypt's state-run agency MENA.
Moussa Abu Marzouk, deputy leader of Hamas' political bureau and a member of the Palestinian negotiating team, had said Wednesday on Facebook that Israeli airstrikes had killed the wife and infant daughter of Mohamed Deif, a commander in the brigades.
Israel and Palestinian factions have blamed each other for the collapse of an Egyptian-sponsored 24-hour truce late on Tuesday, which led to the resumption of armed conflict.
Prior to that, Egypt brokered two 72-hour truce agreements and a five-day ceasefire in a bid to allow more time for negotiations from both sides to reach common ground. However, no Palestinian-Israeli agreement for a ceasefire has been reached so far.
In a press statement issued on Wednesday morning, Egypt's foreign ministry expressed "deep regret" over the resumption of armed confrontations between Palestinian factions and Israel in the warn-torn Gaza Strip.
Cairo warned that the new clashes would "definitely lead to more casualties and injuries among innocent civilians."
"Egypt maintains its bilateral connections with both Palestinian and Israeli sides to urge them to accomplish a new ceasefire deal and continue their positive involvement in the negotiations," the statement said, stressing the importance of building on what has been achieved in the indirect talks so far.
At least 2,058 Palestinians, mostly civilians, and 67 Israelis, mostly soldiers, have been killed since Israel's offensive on Gaza began on 8 July.