Israel has kept up its air and naval bombardments of the Gaza Strip for a seventh day, despite growing international pressure for a ceasefire.
At least 187 people, including 31 children, have been killed as of Monday and more than 1,200 people have been wounded.
The European Union said it was in touch with "all parties in the region" to press for an immediate halt to the hostilities, a day after US Secretary of State John Kerry offered to help secure a Gaza truce.
Britain and Germany have called for a truce with William Hague, the UK foreign secretary, calling for an immediate de-escalation.
Egypt and Qatar are seen as potential mediators but peace efforts were complicated by Hamas' rejection of a mere "calm for calm" in which both sides hold their fire in favour of wider conditions including prisoner release and an end to Israel's Gaza blockade.
Israeli Radio, quoting Egypt's state-news agency, said on Monday that Kerry will arrive in Cairo on Tuesday to discuss a ceasefire.
The Israeli army said its aircraft and naval gunboats attacked dozens of targets in the Gaza Strip where hospitals are overwhelmed and struggling with few resources to treat the steady stream of casualties.
Meanwhile, Palestinian fighters fired more than 20 rockets into Israel on Monday, slightly wounding a boy in the town of Ashdod. Later in the day the army said that a rocket fire wounded two young girls in Beersheba.
The Palestinian Foreign Minister Riad al-Maliki met with the Arab League Secretary General Nabil al-Arabi in the Egyptian capital, Cairo, to discuss the ongoing violence.
Monday's meeting comes a day after Palestinian President Mahmoud Abbas wrote a letter to the United Nations requesting the international body to place Palestine under international protection.
In the letter, Abbas urged UN Secretary General to take all "effective measures required to establish a protection system for Palestine with the aim of ensuring the protection of the Palestinian people from the Israeli aggression, continued occupation and violation of international law, in particular its escalation and bombardments against the civilian population in the Gaza Strip".
Israel has maintained that it was targeting Hamas, who have fired more than 900 rockets into Israel since the escalation of violence began on the July 7. Most of them were intercepted by the "Iron Dome" defence missile system.
Threat of ground incursion
Israel launched "Operation Protective Edge," a military campaign on Gaza, in which more than 1,300 targets have been hit in air-strikes, including family homes and a rehabilitation centre for the disabled.
At least 1,280 people have been wounded in the offensive and more than 17,000 people are sheltering in UN compounds in the densely-populated Palestinian enclave.
A Gaza-based Palestinian human rights group, al-Mezan, said that at least 869 homes have been destroyed or damaged in Israeli bombardment.
Meanwhile, Israel's army announced that it had shot down a drone from Gaza, and that its Iron Dome intercepted one rocket over Tel Aviv.
|INTERACTIVE: Gaza Under Attack
Al Jazeera's Bernard Smith, reporting from the border with Gaza in southern Israel said: "[At least] 36,000 Israeli reservists have been told to report to duty and they will be reporting to Israel-Gaza border. Nobody's telling us that there is going to be a ground offensive, but Israel's army is certainly making all the preparations for one should the order come from the army's political masters."
Meanwhile, clashes erupted in central Paris as thousands of people protested against Israel and in support of Gaza.
Protesters also rallied across Asia to condemn the Israeli offensive, with 3,000 gathering in Sydney and hundreds more in Hong Kong, New Delhi and Jakarta.