(This post was last updated at 5:15 p.m. ET.)
Two assailants, armed with a gun, knives and axes, launched an attack on worshippers at a Jerusalem Synagogue on Tuesday. It left five dead and at least six others wounded.
The U.S. State Department said three of the four killed were dual American and Israeli citizens. A policeman injured in the attack died late Tuesday, Haaretz reported.
The New York Times reports police officers rushed to the scene, and the assailants were killed during a firefight with police.
"Later on Tuesday, Israeli security forces moved into the slain attackers' neighborhood of Jabel Mukaber and clashed with residents, arresting nine people, police said. No details were available on the charges.
" 'We're continuing to search the neighborhood to make sure there are not any further terrorists,' Rosenfeld said."
On his Twitter feed, Israeli Prime Minister Benjamin Netanyahu said he would meet with his Security Cabinet later today.
"This is the direct result of incitement being led by Hamas [and Palestinian Authority President Mahmoud Abbas], incitement which the [international] community is irresponsibly ignoring," Netanyahu said. "We will respond with a heavy hand to the brutal murder of Jews who came to pray and were met by reprehensible murderers."
U.S. Secretary of State John Kerry, who was meeting with his British counterpart in London, called the attack "pure terror" and called on Palestinian leaders to "condemn this in the most powerful terms."
According to the Times, Abbas also issued a statement condemning "the killing of civilians from any side" and "the whole cycle of violence."
Of course all of this comes as tensions in the region mount over the closure of the Al-Aqsa Mosque compound, which Jews call the Temple Mount.
As NPR's Emily Harris reported, because the site is holy to both sides, Jews and Muslims have clashed over access.
"The issue is of such sensitivity that even when Israel captured the Old City of Jerusalem during the war of 1967 it handed control of the compound back to an Islamic religious authority which continues to administer it to this day.
"In recent times some religious Jews have begun to argue for a change in the status quo which would also allow them to pray there — any hint of such change is viewed with deep anger in the Islamic world.
"[Today's] attack happened at a religious seminary site on Harav Shimon Agassi Street — home to a largely Orthodox Jewish community in the Har Nof neighbourhood. Among those killed was Rabbi Moshe Twersky, 60, head of the seminary."
State Department Spokeswoman Jen Psaki identified the three U.S. citizens as Mosheh Twersky, Aryeh Kupinsky and Cary William Levine.
Update at 11:49 a.m. ET. Obama Condemns Attacks:
Speaking to reporters Tuesday morning, President Obama condemned the attacks in the "strongest terms."
"Too many Israelis have died; too many Pals died," he said. "This kind of extremism threatens a spiral from which it's hard to emerge."