By RYAN GORMAN
Three of the four rabbis killed Tuesday in an Israeli synagogue during a frenzied attack by Palestinian militants are American, authorities said, the other is British.
Rabbis Aryeh Kopinsky, 43; Calman Levine; Moshe Twersky, 59; and Avraham Shmuel Goldberg, 58, were hacked, stabbed and shot to death around 7:00 a.m. by two unnamed terrorists, according to police. A cop also injured in the assault died early Wednesday morning.
Twersky, a well-known Jewish scholar and the son of a Harvard University lecturer, has already been laid to rest following a massive funeral procession through the holy city.
The first three men are dual U.S.-Israeli citizens and fourth is a dual British-Israeli citizen, authorities told CNN. The FBI is now involved in the murder investigation because U.S. citizens were killed.
Two militants -- identified to the New York Times by relatives as cousins Odai Abed Abu Jamal, 22, and Ghassan Muhammad Abu Jamal, 32 -- stormed the west Jerusalem synagogue wielding knives, axes an a handgun, according to reports.
"They carried out this operation because of the fire in their hearts -- they were under pressures, pressures, pressures and in one ripe moment, the explosion took place," a relative told the Times.
"I say in full mouth, it is a religious war which Netanyahu has started," the relative added. "It will end the way we like."
The cousins' personal intifada ended when they were killed in a shootout with police responding to calls for help from the roughly 30 people in the synagogue at the time of the attack, according to the Jerusalem Post.
Six other people were injured during the attack, including two police officers, and have been rushed to a nearby hospital, police told CNN. The cop later succumbed to his injuries.
"To see Jews wearing tefillin and wrapped in the tallit lying in pools of blood, I wondered if I was imagining scenes from the Holocaust," Yehuda Meshi Zahav, the veteran leader of a religious emergency-response team, told the Times of the ritual straps and prayer shawls worn by the worshipers.
"It was a massacre of Jews at prayer."
Wintesses described the horrific assault that left pools of blood everywhere and shattered the calm of an otherwise ordinary Tuesday.
"I turn around and I see a man with a pistol who starts shooting point blank at people next to him," Rabbi Yosef Pasternak told Israeli radio, according to the Times.
"Immediately after, someone enters with a knife, a butcher-type knife, and also goes on a rampage in all directions," Pasternak recalled, adding he escaped death by hiding under a chair.
Another Rabbi inside the building as the attack unfolded said he and his 13-year-old nephew also hid from the attackers under chairs. Blood spattered on the young boy as he cowered in fear.
"People were in the middle of prayer and people could not respond," said Rabbi Shmuel Pinchas, according to the Times. "There is nowhere to hide as the synagogue is closed on all sides."
Officials immediately condemned the attack.
Israeli Prime Minister Benjamin Netanyahu called the slaughter "the direct result of the incitement" stoked by Palestinian leadership, and called on his military to "respond with a heavy hand to the brutal murder of Jews who came to pray and were eliminated by despicable murderers."
Palestinian Prime Minister Mahmoud Abbas also denounced the attacks.
"We condemn the killing of civilians from any side," he said in a statement. "We condemn the killings of worshipers at the synagogue in Jerusalem and condemn acts of violence no matter their source."
U.S. Secretary of State John Kerry had earlier called on the Palestinian government to condemn the attack, which he said was "a pure result of incitement.
"The Palestinian leadership ... must begin to take serious steps to restrain any kind of incitement that comes from their language, from other people's language, and exhibit the kind of leadership that is necessary to put this region on a different path," said Kerry.
Members of Hamas, previously classified by the West as a terror organization but also voted into power during democratic elections in Palestine, praised the attacks as "a normal reaction to the Israeli oppression."
Another Hamas leader, in a Facebook post, hailed the attackers as heroes and called for more assaults in the future.
"The new operation is heroic and a natural reaction to Zionist criminality against our people and our holy places," wrote Mushir al-Masri. "We have the full right to revenge for the blood of our martyrs in all possible means."
The Popular Front for the Liberation of Palestine has since taken credit for the brutal attack, but a police spokesperson told the Times that officials are still trying to determine if other parties were also involved.
Unrest over the attacks has led police to tighten their grip over several neighborhoods in the predominantly Muslim areas of eastern Jerusalem, according to BuzzFeed.
Images from Rafah, in Gaza, show heavily armed, masked militants handing out cookies to people celebrating the attack.
Masses of jubilant Palestinians poured into the streets to join in the morbid revelry as posters of the alleged attackers were cheered.
Palestinian radio hailed the cousins as "martyrs," according to the Post, and loudspeakers at mosques cheered the men on.
"Hamas calls for the continuation of revenge operations and stresses that the Israeli occupation bears responsibility for tension in Jerusalem," a Hamas spokesperson told the Post.
The attack came only hours after the Israeli government drew criticism for authorizing the building of a further 200 homes in east Jerusalem.
Kerry said through a spokesperson that he was "deeply concerned" by the decision, and expressed fears it would only further escalate tensions between the two constantly-at-odds countries.
Tuesday's attack was the worst on a synagogue in the country since 2008, it will no doubt only pour gasoline on the raging inferno of mutual Palestinian-Israeli hatred.