Israel and Hamas' fragile five-hour "pause" in hostilities has been threatened as the IDF (Israeli Defence Forces) said it had stopped an attack by 13 Gaza gunmen who had crossed into its territory.
Army spokesman Lt Col Peter Lerner said the gunmen were 250 metres inside Israeli territory when they were spotted by Israeli aircraft, with one militant killed and the others escaping back over the border.
The tunnel the men came through from the southern Gaza Strip towards the southern Israeli community of Sufa. A raw video of the militants coming into Israel shows a number group together before they are fired on.
“We knew this would come. We knew specifically about this tunnel. We knew Hamas would try in any way it can,” IDF Spokesman Brigadier General Moti Almoz told Israel's Channel 2.
“This attack was meant to be a killing spree in one of the villages nearby,” Almoz said, adding that the area had seen numerous rocket attacks in the hours before, which he described as a "foil" for the infiltration.
Thursday's UN-brokered truce is timed to allow Gazans, many of them trapped inside for the entire nine-day bombardment of the Strip, to gather food, water and medical supplies. On Wednesday four children were killed by Israeli shelling as they played on the beach, outside the hotel where several journalists were staying.
NBC News correspondent Ayman Mohyeldin reported that the four children killed were from the same family, aged between 9 and 11-years-old. An Israeli spokesperson told Reuters they were checking the report of the attack. A spokesman for the Gaza Health Ministry called it a "cowardly crime".
The Israeli military said it was "carefully investigating" the incident, the BBC reported.
"Based on preliminary results, the target of this strike was Hamas terrorist operatives," a spokesman said. "The reported civilian causalities from this strike are a tragic outcome."
More than 200 Gazans and one Israeli have been killed in the onslaught thus far. Israeli tank fire also hit a house in southern Gaza, killing three people, just minutes before a five-hour truce went into effect.
Large queues began to form outside shops and banks as the ceasefire began, with workers repairing damaged water and electricity infrastructure.
One of the IDF's former commanders, Israel Ziv, said the attack on the border by the militants was timed to o-ordinate with the ceasefire. “It is not random," the Times of Israel reported him as saying. "It shows how cynical Hamas can be.”
Radio stations in Gaza were reporting that the militants had managed to kill and wound Israeli soldiers in the attack on the border, but Israeli media has reported there were no casualties.
Israel had agreed to a "unilateral humanitarian pause" brokered by UN special co-ordinator for the Middle East peace process Robert Serry. Hamas spokesman Sami Abu Zuhri said its militants would respect the temporary ceasefire and refrain from firing rockets.
Egypt put forward a ceasefire plan on Tuesday which was accepted by Israel but Hamas rejected, saying it had not been consulted. Palestinian president, Mahmoud Abbas has travelled to Cairo to meet Egyptian President Abdel Fattah al-Sissi in the hours following the rejection, along with a senior official from Hamas Mussa Abu Marzuq, to see if the Egyptian proposal could be salvaged.
Hamas insists that the proposal include measures to ease the punishing blockade on the Gaza Strip, and the opening of Egyptian border crossing. It has a natural suspicion of al-Sissi and Egypt's current regime, which has banned its parent organisation the Muslim Brotherhood and persecuted many of its followers.
Hamas in turn apparently proposed a 10-year peace deal, according to Israel's Ma'ariv newspaper, with conditions including the release of Palestinian prisoners, the opening of Gaza-Israel border crossings, the establishment of a seaport and airport in Gaza, and international forces patrolling the borders, not Israelis.
Israel has repeatedly insisted that its stated aim is to destroy the leaders and resources of terror cells that launch rockets at its southern civilians, carrying out air strikes on 37 targets in Gaza since midnight on Wednesday until the truce commenced.
The IDF claims 1,377 rockets have been fired from Gaza since the start of Operation Protective Edge. The United Nations reports that most of those killed in densly-populated Gaza have been civilians.