David Cameron, US president Barack Obama and other world leaders agreed there needs to be a lasting ceasefire in Gaza as the Israeli prime minister said his country must be ready for a “prolonged” military operation in the Palestnian enclave.

The Prime Minister, Mr Obama, German chancellor Angela Merkel, French president Francois Hollande and Italian prime minister Matteo Renzi called for an urgent and lasting ceasefire in Gaza.

In a read-out of a joint call between the leaders this afternoon, a No 10 spokeswoman said: “The leaders discussed the deteriorating situation in Israel and Gaza and agreed on the urgent need for a lasting ceasefire in Gaza and Israel, backing the efforts of the Egyptian government to achieve this.

“They noted that the fighting will not lead to lasting peace or security for either Israelis or Palestinians.”

Smoke rises after an Israeli strike over the southern Gaza Strip. Photo: Jinipix/Israel Sun

Smoke rises after an Israeli strike over the southern Gaza Strip. Photo: Jinipix/Israel Sun

They spoke as Israeli premier Benjamin Netanyahu warned his country would act “aggressively and responsibly” until its mission in the Palestinian territory was complete.

In a televised speech, Mr Netanyahu appeared to widen the the scope of Israel’s objectives, saying the demilitarisation of Gaza must be part of any solution to the conflict.

He said:””We need to be ready for a prolonged campaign,” he said. “We will continue to act aggressively and responsibly until the mission is completed to protect our citizens, soldiers and children.”

More than 1,000 Palestinians, mostly civilians, have been killed in the three week conflict during which Israel has said it wants to destroy Hamas’s ability to fire rockets into Israeland dismantle a network of Hamas military tunnels near the border.

Israel has lost 52 soldiers and three civilians since the conflict began.

Hamas spokesman Sami Abu Zuhri was defiant in the face of Mr Netanyahu’s comments, saying Israel would “pay the price for the massacres against civilians and children”.

Meanwhile, the Israeli army said Gaza militants had infiltrated Israel and opened fire on soldiers. The army said it killed five of the militants and was continuing to search the area.

In Gaza, a military strike on a park killed ten people, nine of whom were children, but Israeli and Palestinian authorities blamed each other for the attack.

UN secretary-general Ban Ki-moon has reinforced the Security Council’s call for “an immediate and unconditional humanitarian ceasefire” in the Gaza war and demanded thatIsrael and Hamas end the violence “in the name of humanity”.

In the conference call, the leaders also discussed the rapidly deteriorating situation in Libya and said the UN had an important role to play in helping the political process in the north African nation restore stability.

They also touched on the situation in Iraq, where the extremist Islamic State in Iraq and the Levant (Isis) have taken control of swathes of territory in recent weeks.

The No 10 spokeswoman said: “(The leaders) also touched on Libya given the worsening security situation and agreed that the United Nations has a vital role to play to facilitate the political process that could help to restore stability in the country.

“Finally, they discussed the situation in Iraq and progress towards establishing an inclusive government that represents all Iraqis.”