Three Americans are among five people killed during a brutal terror attack Tuesday at a Jerusalem synagogue carried out by two Palestinians wielding a meat cleaver and gun.
"We are viewing this as a terrorist attack," said police spokesman Micky Rosenfeld, who confirmed the four dead and that the two assailants were killed by police.
The slain Americans were identified as Aryeh Kupinsky, Kalmen Levin and Moshe Twersky by Fox News. Another eight people were injured in the attack on the Kehillat Bnei Torah synagogue in the ultra-Orthodox Har Nof neighborhood in the western part of Jerusalem.
The Popular Front for the Liberation of Palestine has said it is responsible for the attack, which it called a "heroic operation," and referred to the attackers as "martyrs."
Palestinian revelers in the Gazan city of Rafah also handed out candy and brandished axes and posters of the suspects in praise of the deadly attack, according to the Jerusalem Post.
Israeli Prime Minister Benjamin Netanyahu has pledged to respond with a "heavy hand," Reuters reported, and immediately ordered the demolition of the attackers' homes, as well as homes of Palestinians who carried out several other recent attacks.
He also accused the Palestinian President Mahmoud Abbas of instigating the violence that led to the attack.
"We will respond with a heavy hand to the brutal murder of Jews who came to pray and were killed by lowly murderers," Netanyahu said.
Hamas has also praised the attacks on the synagogue, blaming Israeli occupation of Palestinian settlements for the violence.
"Hamas calls for the continuation of revenge operations and stresses that the Israeli occupation bears responsibility for tension in Jerusalem," Hamas spokesman Sami Abu Zuhri said.
Israel and Palestinian militant group Hamas have engaged in violent conflict since July, leading to the deaths of at least 2,100 Palestinians before a long-term ceasefire was reached on Aug. 26.
U.S. Secretary of State John Kerry called the attacks on the synagogue "an act of pure terror," and CNN has noted that the FBI will investigate the attack, as three victims were U.S. citizens.
"This morning, today, in Jerusalem, Palestinians attacked Jews who were praying in a synagogue. People who had come to worship God in the sanctuary of a synagogue were hatched and hacked and murdered in that holy place in an act of pure terror and senseless brutality and murder," Kerry said.
"Our hearts go out to all Israelis for the atrocity of this event and for all the reminders of history that go with it," he added. "This simply has no place in human behavior, and we need to hear from leaders who are going to lead their people to a different place."