A massive crowd of mourners gathered in Jerusalem Tuesday just hours after four Israeli worshipers -- all of whom held either dual U.S. or British citizenship -- were killed by Palestinians wielding axes and a gun, Israeli police spokesman Micky Rosenfeld told CNN.
At 7 a.m. local time, Aryeh Kopinsky, 43; Calman Levine, 50; Moshe Twersky, 59; and Avraham Shmuel Goldberg, 58, were praying in a synagogue in the Har Nof neighborhood, an ultra-Orthodox community on the outskirts of Jerusalem where many people from Western nations live.
Kopinsky, Levine and Twerksy had dual U.S.-Israeli citizenship, the Jerusalem Post reports.
They were slain while wearing prayer shawls, said Israeli Prime Minister Benjamin Netanyahu, who called for international condemnation of the violence and ordered the attackers' homes destroyed.
Goldberg is a British-Israeli national, authorities said. He's from Liverpool, according to the Liverpool Echo and used to live in London's Golders Green neighborhood, which is known for its large Jewish population.
Levine leaves behind five children and nine grandchildren, the Post reports.
Twersky is originally from Boston, according to the newspaper, and his father was Isadore Twersky. The elder Twersky was an internationally renown rabbi and philosopher as well as a professor of Hebrew literature at Harvard University. When he died in 1997, the Harvard Crimson called him a pioneer of Jewish thought.
Moshe Twersky's grandfather was Joseph B. Soloveitchik, who is considered a founding father of modern Orthodox philosophy.
A New York Times obituary on Isadore Twersky says that Moshe Twersky had two brothers who were rabbis.
Isadore Twersky formerly directed the Center for Jewish Studies at Harvard.
"I know that I speak for all of us in the CJS community when I say that we are heartbroken at the news of this unspeakable act of sacrilegious cruelty,'' Eric Nelson, the director of the center, told CNN. "Our thoughts and prayers are with the Twersky family at this terribly sad and difficult time."
Moshe Twersky graduated from Boston's Maimonides School in 1973, the school said in a statement, adding that "the Maimonides School Family is engulfed in grief and outrage."
He had lived in Jerusalem for the past 30 years, the school said, and is survived by his wife, Bashy, their five children and many grandchildren.
Rosenfeld said that police responded shortly after the attack began and shot and killed the attackers -- two cousins from East Jerusalem.
Tuesday's violence is the deadliest attack in Jerusalem since a man with an automatic weapon killed eight seminary students in March 2008.
But the city has been on edge lately after a series of stabbings and vehicles attacks.
Netanyahu's office called the attack "the direct result of incitement being led by Hamas" and Palestinian Authority President Mahmoud Abbas, referring first to the Palestinian group that controls Gaza and next to the Fatah movement leader in control of the West Bank.
Abbas condemned the synagogue bloodshed, WAFA reported, while stressing the need to end the causes of such attacks like tensions over what Jews call the Temple Mount and Palestinians call al-Aqsa Mosque.
The devastation felt from the slayings was evident among mourners at an eulogy for the four men.
"When four great men, wonderful men, wise in Torah study are slaughtered while praying in public, there is no public grieving greater than that," the man at a microphone said in Hebrew to the large crowd in the street.
A camera captured young women wrapping their arms around each other and swaying. One buried her head in another's shoulder and wept.
"It was horrific," a man described as a witness to the slayings said in a Reuters video. "I can't imagine such attacks would occur to our community. We have to take some time to walk out of the trauma."
At least six people were also wounded in the attack, authorities said.
Funerals for the four victims were to be held Tuesday afternoon.
Mark Regev, spokesman for Netanyahu, vowed that Israeli police presence will be increased. "We've got to make sure there are no copycat attacks," he said on CNN's "New Day."
"We're going to be tough ... with the terrorists," Regev said.
Netanyahu summoned top aides to a "security consultation" later Tuesday in Jerusalem, his office announced.
U.S. Ambassador to Israel Dan Shapiro posted online that the "terrorist attack ... represents a barbaric new low in the sad and outrageous history of such attacks.
"Murdering worshipers at prayer in a synagogue is an act if pure, unadulterated evil," he wrote. "On behalf of the United States government and the American people, I condemn this terrorist attack in the strongest possible terms."
President Barack Obama said Tuesday that "there is and can be no justification for such attacks against innocent civilians."
"At this sensitive moment in Jerusalem," Obama continued, "it is all the more important for Israeli and Palestinian leaders and ordinary citizens to work cooperatively together to lower tensions, reject violence, and seek a path forward towards peace."