Israeli Prime Minister Benjamin Netanyahu said his country must prepare for a protracted conflict in the Gaza Strip, ending any hopes of a quick end to fighting that has cost over 1,000 lives.
In a televised statement, he said that any solution to the crisis would require the demilitarisation of the Palestinian territory - which is controlled by Hamas.
Mortar strikes in Israel have left at least four people - understood to be soldiers - dead, according to Israeli reports.
Israeli Prime Minister Benjamin Netanyahu pledged tougher military action against Hamas after the attacks, as bloodshed in the Middle East conflict continues.
He also warned that Israel must be prepared for a protracted Gaza campaign.
Israeli prime minister Benjamin Netanyahu has said "Hamas will pay" in response to the deaths of three kidnapped teenagers.
He added the teenagers "were kidnapped and murdered in cold blood by wild beasts".
The bodies of the boys - who went missing on June 12 - were discovered under a pile of rocks - after a huge operation by Israeli forces.
Israel immediately accused Hamas of being behind the kidnapping.
Three teenagers missing in the West Bank have been kidnapped by a terrorist group, Israel's prime minister said.
Naftali Frenkel and Gilad Shaar, both 16, as well as 19-year-old Eyal Yifrach went missing two days ago.
Israeli media named Naftali as a US citizen.
"Our children were kidnapped by a terror group, (there is) no doubt about that," Benjamin Netanyahu said.
Mr Netanyahu said an "intensive operation" was underway to prevent the three teenagers being taken to the Gaza Strip or elsewhere.
The Arab League endorsed Palestinian President Mahmoud Abbas's rejection of Israel's demand for recognition as a Jewish state, as U.S.-backed peace talks approach a deadline next month.
The US want Mr Abbas to make the concession as part of efforts to reach a "framework agreement" and extend the talks aimed at settling the Israeli-Palestinian conflict.
Benjamin Netanyahu has been Israel's first prime minister to make recognition of his country as a Jewish state a requirement for peace.
Israeli Prime Minister Benjamin Netanyahu has paid tribute to Ariel Sharon as "a great warrior and military leader" following his death at the age of 85.
Mr Netanyahu's official spokesperson tweeted:
PM Netanyahu expresses his deep sorrow over the passing of former PM Ariel Sharon:"he was a great warrior and military leader" 1/2
PM Netanyahu on the passing of former PM Ariel Sharon: "His memory will live forever in the nation's heart" 2/2
Israel's Prime Minister Benjamin Netanyahu has called the nuclear deal with Iran "an historic mistake" and said it has "made the world a much more dangerous place".
He said that the international community appeared to have switched position in not calling for a complete end to all uranium enrichment, and accused Iran of taking "cosmetic steps which it could reverse easily within a few weeks".
"Without continued pressure [on Iran], what incentive does the regime have to take serious steps which actually dismantle its nuclear weapons capability?"
"Israel is not bound by this agreement," he added.
Israel's Prime Minister Benjamin Netanyahu has described the deal on Iran's nuclear programme as an "historic mistake".
President Barack Obama plans to talk to the Israeli prime minister later today about Netanyahu's concerns, a senior US official said.
Israel has repeated its conviction that the offer of sanctions rollbacks for Iran would only achieve more time for Iran to master nuclear technology and amass potential bomb fuel.
Prime Minister Benjamin Netanyahu told Channel Rossia in Moscow: "I think right now the international community ... has all the leverage to roll back its [Iran's] nuclear making capacities.
"It's a pity, just when they have this maximum leverage, that they're backing off and essentially giving Iran an unbelievable Christmas present - the capacity to maintain this breakout capability for practically no concessions at all."
As world leaders gather in Geneva to discuss Iran, Israel has called for the sanctions to remain in place until Iran has dismantled its entire uranium enrichment programme.
"I understand that the Iranians are walking around very satisfied in Geneva - as well they should be, because they got everything and paid nothing," Israeli Prime Minister Netanyahu said.
"Iran got the deal of the century and the international community got a bad deal," he added.