Updated 17.26
Israel has accused Hamas of misfiring two rockets - one of which struck Gaza's main hospital and the other a refugee camp, killing seven children.
Palestinian police and medics had earlier suggested Israeli missiles for the strikes on Al-Shifa Hospital in Gaza City, causing casualties, and a nearby park in Al-Shati refugee camp.
A Palestinian official said at least 10 people in total were killed in the strike on a playground in the camp park, and a further 46 injured.
However, the Israel Defence Forces (IDF) denied responsibility for the attacks and said it had not been operating in the area at all.
Lieutenant Colonel Peter Lerner, an Israeli army spokesman, said. "This incident was carried out by Gaza terrorists whose rockets fell short and hit the Shifa Hospital and the Beach (Shati) camp," he said.
The Israeli Defence Forces (IDF) also tweeted: "Since the beginning of the operation #IDF has documented approximately 200 rockets & mortars that landed short within #Gaza."
Reporter David Bowden, who visited the hospital in Gaza City, said "It is a mess down there. I've seen injured children, some very badly injured and not so badly injured, and in the morgue I have seen dead children".
Israeli media - meanwhile - reported four people had been killed in Gaza mortar strikes on southern Israel.
The attacks came after UN Secretary-General Ban Ki-moon likened the conflict to a "manmade hurricane", saying "whole neighbourhoods have been reduced to rubble".
He demanded an end to the violence "in the name of humanity" and accused Israeli Prime Minister Benjamin Netanyahu and Hamas leader Khaled Mashaal of being irresponsible and "morally wrong" for putting their own people at risk of being killed.
The Secretary-General called on them to demonstrate "political will" and compassionate leadership" to end the suffering.
He said Gaza was in a "critical condition" following Israeli strikes resulting in the deaths of hundreds of Palestinian civilians, which he said raised "serious questions about proportionality".
Addressing journalists in New York, Ban Ki-Moon reiterated this message:
Several temporary truces have been observed and broken on a weekend when the Palestinian death toll topped 1,000. Those killed during this conflict include 20 members of one family, including eleven children, reported by OCHA using protection cluster data, as killed in one airstrike early on July 26th before the ceasefire came into effect.
According to Ministry of Health figures, 6,030 Palestinians have been injured in the current conflict.
Some 43 Israeli soldiers have also been killed since their military operation began on July 8th, while three civilians have died from rocket fire into Israel.
The United Nations Relief and Works Agency (UNRWA) said that during the ceasefire, high numbers of Palestinian dead were reported to have been retrieved from the rubble of destroyed buildings.
More than 200 children killed (218), more than 1,500 injured (1,516) in #Gaza. UNICEF calls for an immediate end to the violence #ceasefire
— UNICEFpalestine (@UNICEFpalestine) July 27, 2014
Riyad Mansour, the Palestinian representative to the UN, said he was "disappointed" a formal resolution demanding Israel withdraw its forces from the Gaza Strip had not been agreed.
"They should have adopted a resolution a long time ago to condemn this aggression and to call for this aggression to be stopped immediately" he said.
Israeli ambassador Ron Prosor added "Miraculously (the statement) doesn't mention Hamas. It doesn't mention the firing of rockets. You don't have to have the IQ of a rocket scientist to understand that if rockets are falling on you, you are allowed to defend yourself".
On Sunday, US President Barack Obama called Israel Prime Minister Benjamin Netanyahu to press for an immediate truce.
The US President said Israel had a right to defend itself but reiterated his country's "serious and growing concern" about the loss of life on both sides and the "worsening humanitarian situation in Gaza".
A temporary, 24-hour extension to a humanitarian ceasefire started at 2pm (noon UK time) yesterday ahead of the Muslim festival of Eid.
Humanitarian aid being distributed at Jabalia Preparatory Girls School - one of the UN shelters in Jabalia camp
Reporter Sherine Tadros, reporting from Gaza City, said more than 160,000 civilians had sought refuge in dozens of temporary shelters and were suffering from major food and water shortages.
As well as calling for an immediate truce, the Security Council statement set out a longer-term aim of two democratic states, Israel and Palestine, "with secure and recognised borders".
