A 17-year-old Israeli girl has been killed in a bomb attack near a Jewish settlement in the occupied West Bank, the Israeli military says.
Rina Shnerb had been hiking with her brother Dvir and her father Eitan near a natural spring outside Dolev when an improvised explosive device blew up.
Dvir and Eitan were seriously wounded by the blast and were evacuated by helicopter to a hospital in Jerusalem.
Prime Minister Benjamin Netanyahu said it was a "harsh terrorist attack".
"We will continue to strengthen settlement. We will deepen our roots and strike at our enemies," Mr Netanyahu said.
"The security arms are in pursuit after the abhorrent terrorists. We will apprehend them. The long arm of Israel reaches all those who seek our lives and will settle accounts with them."
President Reuven Rivlin said: "This was a despicable attack against innocent people going about their daily lives in peace."
Israeli troops were quickly deployed around Dolev, which is about 15km (9 miles) north of Jerusalem and near the Palestinian village of Deir Ibzi, following the bombing. The military said they were searching the area, setting up roadblocks, and boosting security.
Eitan Shnerb, who is a rabbi, later addressed his daughter's funeral in their hometown of Lod, in central Israel, by telephone from his hospital bed, the Times of Israel newspaper reported.
"We are trying to be strong here in the Land of Israel, the people of Israel. Rina believed in that," he was quoted as saying. "Our response to the murderers is that we are here and we are strong and we will prevail."
The US ambassador to Israel, David Friedman, tweeted that he was "heartbroken and outraged by the brutal terrorist attack".
In a speech in the Gaza Strip, the leader of the militant Palestinian Islamist movement Hamas praised the attack but did not say that it was behind it.
Israeli military spokesman Brig Gen Ronen Manelis told the Jerusalem Post that security forces had not yet determined whether those behind the attack were part of an established group or had acted alone.
He noted that there had been a recent increase in militant activity and violence in the West Bank and Gaza.
Last Friday, two Israelis were injured near the settlement of Elazar in what police said was a car-ramming attack. The alleged assailant, a Palestinian man, was shot dead at the scene.
Earlier this month, an off-duty Israeli soldier was stabbed to death near the settlement of Migdal Oz. Israeli security forces subsequently arrested two Palestinian men in connection with the attack.
More than 600,000 Jews live in about 140 settlements built since Israel's 1967 occupation of the West Bank and East Jerusalem. The settlements are considered illegal under international law, though Israel disputes this.