A Palestinian infant was killed in the West Bank early Friday morning in an arson attack, apparently by Jewish extremists.

Two homes in the Palestinian village of Duma, south of Nablus, were set alight, and the Hebrew words “Revenge” and “Long live the king messiah” were spray-painted on their walls, alongside a Star of David.

Palestinian medical sources said the child, Ali Saad Dawabsha, was 18 months old.

The infant’s parents, as well as his 4-year-old brother, were all injured and evacuated to the hospital. They were said to be in moderate-to-serious condition, with burns on large parts of their bodies.

A Star of David and the Hebrew word 'Revenge' are spray-painted on the walls of a Palestinian home which was burned down by arsonists on July 31, 2015 in the Palestinian village of Duma, near Nablus (Zacharia Sadeh/Rabbis for Human Rights)

A Star of David and the Hebrew word ‘Revenge’ are spray-painted on the walls of a Palestinian home, which was burned down by arsonists in the Palestinian village of Duma, near Nablus, on July 31, 2015. (Zacharia Sadeh/Rabbis for Human Rights)

The two homes — one of which belonged to the Dawabsha family, and the other, which was empty at the time — were set on fire by unidentified assailants at around 2:00 a.m. According to some reports, the fire was caused by Molotov cocktails that were thrown into the house. Others claimed the home was doused with flammable material and set alight.

The parents woke up and tried to get their children out of the house, but were unable to save their youngest son. Local residents said four men were seen fleeing the scene in the direction of the nearby settlement of Ma’ale Efraim.

The Hebrew phrase 'Long live the king messiah' is spray-painted on the walls of a Palestinian home which was burned down by arsonists on July 31, 2015 in the Palestinian village of Duma, near Nablus (Zacharia Sadeh/Rabbis for Human Rights)

The Hebrew phrase ‘Long live the king messiah’ is spray-painted on the walls of a Palestinian home, which was burned down by arsonists in the Palestinian village of Duma, near Nablus, on July 31, 2015. (Zacharia Sadeh/Rabbis for Human Rights)

A large number of Israeli security forces were reportedly at the scene and investigating the attack. The Israel Defense Forces condemned the “terror attack,” with the military spokesman promising to find the perpetrators of the “very serious incident.”

“We’ve always feared a day would come when arson would take a life,” Zacharia Sadeh, of Rabbis for Human Rights, told Ynet news. “This is a terror attack against innocent people who were asleep in their home.”

He called on Israeli leaders and defense officials to “find the criminals and bring them to justice.”

Dani Dayan, the former head of the Yesha Council settler organization, told Army Radio he hoped those responsible would be caught.

“Such crime must be rooted out without hesitation,” he said. “If anyone is inciting to such crimes, they too should be thrown into jail.”

A man shows a picture of 18-month-old Palestinian toddler Ali Saad Dawabsha who died when his family house was set on fire by alleged Jewish extremists in the West Bank village of Duma on July 31, 2015. (AFP PHOTO / JAAFAR ASHTIYEH)

A man shows a picture of 18-month-old Palestinian toddler Ali Saad Dawabsha who died when his family house was set on fire by alleged Jewish extremists in the West Bank village of Duma on July 31, 2015. (AFP PHOTO / JAAFAR ASHTIYEH)

Right-wing extremists have in recent years carried out various attacks, which involved arson and graffiti, on Arab property in the West Bank and Jerusalem under the “price tag” slogan.

Israeli officials have termed the attacks “Jewish terror” and have vowed to fight this phenomenon.

On Thursday, prosecutors charged a third Jewish suspect in a probe linked to a June arson attack at the Church of the Multiplication of the Loaves and Fishes, the shrine where Christians believe Jesus performed the miracle of the loaves and fishes.

The Shin Bet general security service has described Moshe Orbach, Yinon Reuveni and Yehuda Asraf as part of an “ideological infrastructure” that is small in size and adheres to a belief system that seeks to effect regime change in Israel and “hasten redemption.”