Palestinian mourners shout slogans as they carry the body of Israa Abu Khousa, 6, during her funeral Saturday in Beit Lahiya in the north of the Gaza Strip. She died of injuries from an Israeli airstrike. AFP PHOTO / MAHMUD HAMS/AFP/Getty Images (Mahmud Hams/AFP/Getty Images)

Israel and Islamist militants in Gaza exchanged escalating threats and rocket fire over the weekend, as an Israeli retaliatory airstrike hit a family home in the coastal enclave, killing two Palestinian children.

Hackers associated with the Islamist militant movement Hamas, which controls the Gaza Strip, also managed to interrupt a television broadcast of the popular local version of the “Big Brother” reality show Saturday night to warn Israelis, in Hebrew, that they should stay inside their homes and not venture out onto the streets.

The three-minute propaganda video showed images of dead bodies, called the Israelis murderers of women and children, praised the recent wave of Palestinian knife and gun attacks — and warned that more violence was ahead.

The escalation began Friday night when militants in the coastal enclave fired four rockets at Israel across the Gaza border fence. The projectiles landed in open fields and caused no damage, but they represented one of the largest salvos fired from Gaza since the end of the 50-day summer war in 2014.

Palestinian doctors wheel a wounded 6-year-old girl at al-Shifa hospital in Gaza City after an Israeli air strike in the northern Gaza strip on Saturday. (Mahmud Hams/AFP/Getty Images)

None of the factions in Gaza claimed responsibility for the rocket fire, but Salafist militants are suspected of being behind the attack, possibly launching the projectiles to antagonize their rivals in Hamas.

Israeli military officials say that although the rockets may not have been launched by Hamas, the group is responsible for anything fired from its territory.

Israel responded Saturday night with missiles directed at four Hamas sites, according to the military. One missile, aimed at a Hamas training camp, struck a simple two-room cement home at the perimeter of the site that belonged to Salman Abu Khousa. Two of his children, Yaseen, 6, and Israa, 10, were killed.

“My six children were sleeping with their mother in the next room. Suddenly I heard a huge boom and my wife screaming. I went to the room and found three of the children injured, two badly,” said Abu Khousa, whose home is about a mile from Gaza’s border with Israel.

“Israel will not accept rocket fire of any kind from the Strip at its territory,” Prime Minister Benjamin Netanyahu said Sunday. “The Israel Defense Forces will respond to any such provocation. Israel holds Hamas responsible for all firing carried out from the Gaza Strip toward Israel; Hamas must prevent such firing.”

Israel’s defense minister, Moshe Yaalon, said, “We will act even more harshly if these attempts continue.”

Palestinians look at the damage to a house where medical officials said fragments from a missile fired by an Israeli aircraft killed a 10-year-old Palestinian boy in the northern Gaza Strip on Saturday. The missile was fired hours after militants launched rockets into Israel. (Mohammed Salem/Reuters)

An Israeli military official, who spoke on the condition of anonymity because of security protocols, called the death of the Palestinian children “an unfortunate human tragedy following four rockets launched at the people of southern Israel.”

The Hamas target was hit, the official said, but “it appears that some debris ricocheted approximately 100 meters away and fell through the prefabricated roof, causing the unfortunate loss of life.”

A statement from the Hamas militia, Izzedine al-Qassam Brigades, posted on its website, warned that “the blood of our children will not flow in vain.”

“The occupation must know that patience of al-Qassam Brigades and the resistance factions has its limits,” the group said.

The militia referred to the dead children as martyrs and posted photos of their bodies being prepared for burial Saturday.

“I blame the Israelis for this,” the children’s father said. “Nobody talked to me from the Israeli side. I haven’t received an apology from anyone, and even if they did, what can an apology do for me? Will it bring my kids back?”

Abu Khousa said that he lost his home during the 2014 summer war between Israel and Hamas and that the family had been living in makeshift housing.

The Hamas military training site, basically an open field, was approximately 40 yards from Khousa’s home.

Israeli military officials say Hamas does not want to fight another war with Israel now; instead, they say, the group is busy rearming itself, manufacturing rockets and digging tunnels along the Egyptian and Israeli borders.

A dozen diggers and engineers have been killed in Hamas tunnels that have collapsed in recent months.

Booth reported from Jerusalem.