Israeli military aircraft have killed three top Hamas commanders in southern Gaza, inflicting a heavy blow on the movement's armed wing after failing to kill its top military chief.
And a Hamas warning to foreign airlines to avoid flying into Israel's main airport, appeared to have fallen on deaf ears with air traffic operating as normal, aviation officials said.
Thursday's attack came a day after Israeli Prime Minister Benjamin Netanyahu said that Israel's military offensive in the Gaza Strip may be an extended operation.
The Ezzedine al-Qassam Brigades, Hamas's military wing, confirmed that Mohamed Abo Shamaleh, Raed al-Attar and Mohamed Barhoum had been killed in an Israeli airstrike on Rafah, the Reuters news agency reported.
"The assassination... is a big Israeli crime, which will not succeed in breaking our will or weakening our resistance," spokesman Sami Abu Zuhri said in a statement, warning: "Israel will pay the price."
Al Jazeera's Jacky Rowland, reporting from West Jerusalem, said this looked like a return to Israel's "historical" tactics of targeting senior figures.
"During this renewed round of hostilities we are seeing a different approach, and this could be seen as an acknowledgement that military tactics have not been delivering on several different levels," our correspondent said.
"The previous tactics were not working diplomatically, in fact they have been disastrous, seriously affecting Israel's international prestige and even its relationships with firm allies."
At a news conference on Wednesday in Tel Aviv, Netanyahu said that the war launched on July 8 "will be a continued campaign" aimed at restoring "calm and safety to Israeli citizens".
"Only the guarantee of the safety of Israeli citizens and therefore I will continue to operate with firmness and insistence. Operation Protective Edge is not finished, not for a minute, we are talking about a continued campaign," Netanyahu said.
Netanyahu added that he saw a "new diplomatic horizon" ahead for Israel in the region, alluding to possible diplomacy with Palestinians ahead once the war was over, according Reuters news agency.
"Amid the feeling of dramatic changes that are taking place in the region, I can also add, that there is a new diplomatic horizon for the state Israel," he said.
Hamas spokesman Zuhri denounced Netanyahu's speech as "a pathetic attempt to heal Israel's psyche and the assassination threats of Hamas' leadership reflects the extent of the occupation's violence and their lack of seriousness in achieving a ceasefire".
"These threats will not frighten Hamas leaders. On the contrary, we will continue to protect and defend our people in facing Israeli crimes or foolishness," he said.
Al Jazeera's Jane Ferguson, reporting from Gaza, said the slain commanders had been accused by Israel in the kidnapping of its soldier Gilad Shalit, who was freed in 2011 under a prisoner swap deal with Hamas.
She said that the military wing of Hamas had come out with very defiant statements, including warning international airlines not to fly into Israel's Ben Gurion airport.
"However", said correspondent our said, "the political wing of Hamas, as well as Islamic Jihad [another Palestinian faction] has said that they're willing to return to the talks in Cairo."
She added that that their interest in talks is an "indicator of how both sides ... are aware that whilst they say they're prepared to fight, they also know that they need a political solution at some stage".
Hamas is seeking an end to a seven-year Israeli-Egyptian blockade that has battered Gaza's economy, while Israel wants guarantees that Hamas will disarm.
In nearly a week of indirect talks, Egypt appears to have made little headway in resolving the differences.
Fighting resumed on Tuesday after a week-long truce in Gaza collapsed with both sides blaming each other after Palestinian fighters launched rockets into Israel and Israel attacked "terror sites" inside the besieged enclave.
More than 40 Palestinians have been killed by Israeli air strikes in Gaza since the ceasefire collapsed, raising the total death toll to over 2,035 since the beginning of Israel's "Operation Protective Edge".
In a failed attempt to kill Hamas' military commander Mohammed Deif on Tuesday, Israeli airstrikes also killed Deif's wife and a seven-month-old son at the house of the family they were staying with.
Israel's interior minister Gideon Saar and Netanyahu said that Deif and other commanders were legitimate targets.