Last Updated Jul 28, 2014 1:45 PM EDT
GAZA CITY, Gaza Strip -- A strike on a Gaza park killed 10 people Monday, nine of them children, as Israeli and Palestinian authorities traded blame over the attack and fighting in the Gaza war raged on despite a major Muslim holiday.
A truce between the sides remained elusive as diplomats sought to end the fighting at the start of the Eid al-Fitr holiday, marking the end of the Muslim holy month of Ramadan.
In Israel, meanwhile, the military said a mortar attack on southern Israel caused "deaths and injuries," but did not disclose further details. Israeli media reported that the attack killed at least four people, which saw military helicopters rushing stretchers away to local hospitals.
The Gaza park attack happened as children played on a swing in the Shati refugee camp on the edge of Gaza City, said Ayman Sahabani, head of the emergency room at nearby Shifa Hospital. Sahabani said nine of the 10 killed at the park were children under the age of 12 and 46 were wounded.
The strike on the park occurred a few minutes after the hospital's outpatient clinic was hit, leaving several people wounded. Camera crews were prevented from filming the area of impact at Shifa.
Gaza's police operations room, Civil Defense and Sahabani blamed the attacks on Israeli airstrikes.
Lt. Col. Peter Lerner, an Israeli army spokesman, denied Israel was involved. "This incident was carried out by Gaza terrorists whose rockets fell short and hit the Shifa Hospital and the Beach (Shati) camp," he said.
Gaza's Interior Ministry spokesman Eyad al-Bozum said he believes that shrapnel found in dead bodies and in the wounded is evidence of Israel's role in the incident.
"The occupation claims that Palestinian rockets hit the hospital and the park," he said. "This is an attempt to cover their ugly crime against children and civilians, and because of their fear of scandal and international legal prosecution."
In a text message, Hamas spokesman Sami Abu Zuhri called the strike on the park a "massacre." The Hamas military wing said that in response to the strike, it fired three rockets toward the Israeli port city of Ashdod.
Meanwhile, Israeli Prime Minister Benjamin Netanyahu said Israelis must be "ready for a prolonged campaign" against Hamas in the Gaza Strip. Netanyahu also said in a televised speech Monday that a demilitarization of Gaza must be part of any future solution in the territory.
Earlier Monday, the army announced that Gaza militants had infiltrated into Israel through a tunnel and opened fire on soldiers. Israeli media said five militants were apparently killed in a firefight and that searches in the area were continuing. In a sign that Israel's operation is expanding, the army urged residents of three more Gaza districts to evacuate their homes and head toward the center of Gaza City.
Israeli jets struck several sites in Gaza and rockets continued to fall on Israel, the Israeli military said, disrupting a relative lull.
Israel says it launched its war on Hamas July 8 to halt incessant rocket fire from Gaza. It later broadened the assault into a ground offensive, which is meant to tackle Hamas' network of tunnels which Israel sees as a major threat.
The United Nations on Monday called for an "immediate" cease-fire in the fighting that has already killed over 1,040 Palestinians, 43 Israeli soldiers and three civilians on the Israeli side. On Sunday, President Barak Obama telephoned Netanyahu to push for an immediate end to the conflict.
Netanyahu spoke with U.N. chief Ban Ki-moon, according to a statement from his office, in which he voiced his dismay with the U.N. announcement. "It does not include a response to Israel's security needs and the demilitarization of the Gaza Strip," he said.
In an interview on CBS' "Face the Nation" Sunday, Netanyahu said that Israel is not obliged to continue to abide by cease-fire requests in the Gaza war as long as Hamas continues to fire rockets during those periods. He said Israel had accepted and implemented five cease-fires that Hamas had rejected, adding the Gaza Strip rulers were even continuing to fire rockets during a 24-hour truce they themselves proposed.
"Israel is not obliged and will not let a terrorist organization, a ruthless terror organization, committed to our destruction, to decide when it's convenient for them to stop for a moment, rearm, and continue firing on our citizens and our people," Netanyahu said. "We'll determine what is important for our own security in the way that we can to protect our people, including working against these terror tunnels that they're digging against us. That's how we'll act. We'll just act to protect our people."
Hamas leader Khaled Meshaal told "CBS This Morning" co-host Charlie Rose that he's not ready to recognize Israel as a Jewish state, saying that under Israeli occupation, Israel and a state of Palestine cannot coexist.
"When Israel practically commits itself to withdraw from Gaza completely and the West Bank without any settlements, and if we have Jerusalem as our capital and the return of the refugees is there, then we will reach peace," Meshaal said through a translator in an exclusive interview with Charlie Rose, which will appear in full on PBS.
Israel, which says it launched the war on July 8 to halt relentless Hamas rocket fire on its cities, wants more time to destroy Hamas' rocket arsenal and the tunnels the Islamic militants use to infiltrate Israeli territory and smuggle weapons.