The 13-year-old Israeli stabbed to death by a Palestinian teenager, as she slept in her bedroom in the settlement of Kiryat Arba on Thursday morning, was an American citizen, the State Department said.

Hallel Yaffa Ariel died of her wounds hours after a 17-year-old Palestinian high school dropout from a neighboring village jumped the fence into the settlement, broke into her home and fatally stabbed her.

“We have now confirmed that she is a US citizen,” State Department spokesman John Kirby said during a press briefing.

In a statement issued earlier in the day, Kirby said that Washington “condemned in the strongest possible terms the outrageous terrorist attack this morning in the West Bank where a 13-year-old girl, Hallel Ariel, was stabbed to death in her home.”

“This brutal act of terrorism is simply unconscionable. We extend our deepest condolences to her family,” said the statement from Kirby.

First responders remove a mattress from the home of 13-year-old Hallel Yaffa Ariel, who died of her wounds after she was stabbed by a Palestinian terrorist as she lay in bed at her home in Kiryat Arba, in the West Bank, June 30, 2016. (Hadas Parush/Flash90)

First responders remove a mattress from the home of 13-year-old Hallel Yaffa Ariel, who died of her wounds after she was stabbed by a Palestinian terrorist as she lay in bed at her home in Kiryat Arba, in the West Bank, June 30, 2016. (Hadas Parush/Flash90)

The early-morning stabbing, among the most brazen Palestinian attacks during a nine-month wave of violence that has seen dozens of assaults on Israeli civilians and security forces, drew calls from Israeli leaders for the world to condemn the incident.

“The horrifying murder of a young girl in her bed underscores the bloodlust and inhumanity of the incitement-driven terrorists that we are facing,” Prime Minister Benjamin Netanyahu said. “The entire world needs to condemn this murder, just as it condemned the terrorist attacks in Orlando and Brussels.”

The attack was roundly condemned by other members of international community, including the EU, UK and Germany.

Rina, the mother of Hallel Yaffa Ariel, a 13-year-old girl who was fatally stabbed by a Palestinian terrorist in her home, mourns over her daughter's body during her funeral in the Kiryat Arba settlement, on June 30, 2016. (Gil Cohen-Magen/AFP/Getty Images)

Rina, the mother of Hallel Yaffa Ariel, a 13-year-old girl who was fatally stabbed by a Palestinian terrorist in her home, mourns over her daughter’s body during her funeral in the Kiryat Arba settlement, on June 30, 2016. (Gil Cohen-Magen/AFP/Getty Images)

The German Foreign Office said in a statement that “the stabbing of a 13-year-old girl is a new record in atrocious and cruel acts,” while the head of the European Union’s delegation in Israel, Lars Faaborg-Andersen, “strongly condemned” the attack, adding there was “no excuse for terrorism.”

UK Ambassador to Israel David Quarrey denounced the “horrific terrorist attack, saying there was “no possible justification for murder of 13-year-old girl in her bed.”

Ariel was laid to rest in Hebron on Thursday afternoon at an emotional ceremony attended by hundreds of people, including several senior politicians.

View of the bedroom of Hallel Yaffa Ariel, 13, who was stabbed and killed in a terror attack in the Jewish settlement of Kiryat Arba, in the West Bank on June 30, 2016. (Yonatan Sindel/Flash90)

View of the bedroom of Hallel Yaffa Ariel, 13, who was stabbed and killed in a terror attack in the Jewish settlement of Kiryat Arba, in the West Bank on June 30, 2016. (Yonatan Sindel/Flash90)

Times of Israel staff and AP contributed to this report.