JERUSALEM -- A Jerusalem synagogue turned from peaceful sanctuary to house of horrors within moments Tuesday, after two Palestinian cousins wielding knives, axes and a gun attacked during morning prayers.
Police responded within minutes, shooting and killing the attackers inside the synagogue in West Jerusalem's Har Nof area, said Israeli police spokesman Micky Rosenfeld.
But not before six people had been wounded, and three dual U.S.-Israeli citizens and a British-Israeli citizen had been killed.
The terror attack -- the deadliest in Jerusalem since a man with an automatic weapon killed eight seminary students in March 2008 -- came at a particularly tense time in the Israeli city, and the region at large. It follows a series of recent deadly stabbings and vehicle incidents that, while not the large-scale suicide bombings that defined last decade's second intifada or the rocket attacks from Gaza earlier this year, that have left Jerusalem on edge.
"While Israelis are a tough breed, repeated, totally unpredictable attacks are bound to take their toll," said David Harris, an expert with The Israel Project. "Is a mother going to allow her child to walk to school, to catch a bus to a movie theater or (ride a train) to visit a friend?"
Experts: No third intifada yet -- but little hope, either
After the attack, Israeli Prime Minister Benjamin Netanyahu's office vowed "we will respond with a heavy hand to the brutal murder of Jews who came to pray and were met by reprehensible murderers."
His spokesman Mark Regev told CNN's "New Day" that Israel's police presence will be beefed up, saying, "We've got to make sure there are no copycat attacks."
Netanyahu ordered the demolition of the slain attackers' homes in the East Jerusalem neighborhood of Jabel Mukaber, where Israeli security forces clashed with residents later Tuesday, authorities said. The Palestinians' official WAFA news agency reported 13 were arrested, including an al-Aqsa Mosque guard.
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.
In comments later Tuesday to Israeli military recruits, Israel President Reuven Rivlin said Abbas "did well in condemning the attack," even as he insisted that the Palestinian leader must do more in acting "vigorously against incitement."
Yet in Gaza, Palestinians not only didn't condemn the attack, they celebrated it, according to the Jerusalem Post and photos shared by Israeli military spokesman Peter Lerner.
Hamas -- which has been at odds with Abbas and his Fatah movement -- did not claim responsibility for the bloodshed, though it didn't back away from it either. Sami Abu Zuhri, a spokesman for the group, instead linked the attack to the discovery Sunday of an Palestinian bus driver found hanged in his bus not far from where Tuesday's attack occurred.
Senior Hamas official Ghazi Hamad predicted to Al Jazeera International that "there will be more revolution in Jerusalem, and more uprising."
"Hamas in general supports action against the occupation," Hamad said. "Hamas supports any military action against the occupation anywhere it can be carried out."
Four rabbis killed
A holy book, prayers shawls, the floor and a wall splattered red. Lifeless bodies sprawled on a floor, a few feet from desks and books. A bloodstained cleaver. Toppled chairs, and a shattered pair of glasses.
Those grisly scenes show the horror inside the Jerusalem synagogue, a place where -- just before 7 a.m. -- was a place of calm and peace, where more than 10 people had come to pray.
Officials overseas such as British Foreign Secretary Philip Hammond strongly condemned the killings, and U.S. Ambassador to Israel Dan Shapiro called them "a barbaric new low in the sad and outrageous history of such attacks."
"There is and can be no justification for such attacks against innocent civilians," U.S. President Barack Obama said. "...At this sensitive moment in Jerusalem, 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."
The four killed were all rabbis: Avraham Shmuel Goldberg, 58; Aryeh Kopinsky, 43; Moshe Twersky, 59; and Calman Levine. Goldberg was a dual British-Israeli citizen, and the other three were U.S.-Israeli citizens -- which is why the FBI is investigating the attack, according to a U.S. law enforcement official.
"When four great men, wonderful men, wise in Torah study, are slaughtered while praying in public, there is no public grieving greater than that," said a rabbi who eulogized the men later Tuesday, before their burial.
As to their attackers, police said that they were from East Jerusalem, where Palestinians can move more freely about the city than those living in Gaza, who must pass through stringent checkpoints.
Ma'an, a semi-official Palestinian news agency, identified the attackers as Ghassan Abu Jamal and his cousin Udayy.
Whether their actions were part of a coordinated campaign or a spontaneous reprisal, Tuesday's attack raises the specter of yet more violence against civilians.
The latest wave began earlier this year with the kidnapping of three Israeli teens, who were later found dead. Reprisal attacks, rocket fire and retaliatory airstrikes followed that incident, with more than 2,000 Palestinians and 67 Israelis reportedly killed after weeks of heavy fighting.
Much of the most recent unrest has been centered around Jerusalem. That includes the discovery of the body of Palestinian bus driver Yousuf al-Ramouni on Sunday, the same day an Israeli was stabbed with a screwdriver near central Jerusalem.
'There is no organization'
Last week, a 20-year-old was stabbed and killed in Tel Aviv, and three people were stabbed -- one fatally -- near the entrance to a settlement in the West Bank, the same spot where the three Israeli teens were kidnapped.
Analysts point out that large-scale violence has decreased in Jerusalem in recent years, partly because of increased security but also because Palestinian and Israeli leaders are cooperating behind the scenes.
But former Israeli National Security Adviser Maj. Gen. Yaakov Amidror said the recent acts of violence may be more difficult to stop than in the past because they seem to be carried out by individuals and not planned out and executed by a group.
"There is no organization behind it," he said, noting that all someone has to do is take a knife from their kitchen and attack. "... I don't see any measures that can be taken to stop an individual (like that)."
Hanan Ashrawi, a Palestinian legislator, told CNN that incidents such as the "lynching" of the bus driver "have provoked the Palestinians to the point where many of them are retaliating individually by resorting to violence."
Jerusalem Mayor Nir Barkat -- whose city is about two-thirds Jewish and one-third Arab -- said attacks like the one at the synagogue are "not just an Israeli problem."
"If the world doesn't unite against terrorism and give zero excuses for terrorism, this will haunt he world," he said. "This will happen everywhere in the world."