Jerusalem synagogue attack victims were American and British, police say Israel vowed a harsh response after two Palestinian attackers slashed and shot to death four rabbis who were praying in a Jerusalem synagogue early Tuesday -- an attack that horrified Israelis, drew international condemnation and threatened to further inflame Jewish-Muslim tensions that were already running high over a contested holy site. At least seven Israelis were hospitalized in the wake of the attack, the deadliest in Jerusalem since 2008. The two attackers, shot dead by police units that converged on the scene within minutes, were identified as Palestinian cousins from predominantly Arab east Jerusalem, which has been a flashpoint for attacks in recent months. The attackers -- armed with cleavers and handguns and said to have been shouting "God is great!" -- burst into the synagogue in the ultra-Orthodox Jerusalem neighborhood of Har Nof during morning prayers, witnesses said. Many devoutly religious immigrants to Israel have settled in the area, and three of the four rabbis killed held American citizenship, the State Department said. A fourth was a Briton, according to Israeli officials. The White House identified the slain Americans as Aryeh Kupinsky, Cary William Levine and Moshe Twersky. The statement did not provide hometowns. President Obama condemned the attack but said "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." Witnesses described panic and pandemonium during the attack, with the dead and wounded crumpling to the floor, clutching bloodied sacred texts. Those who managed to make their way out of the house of prayer bursting onto the street and screaming for help. For many Israelis, the specter of a calculated attack on Jews at prayer, in ritual garments, carried chilling overtones of historic persecution. "Jewish worshippers lay dead in pools of blood, still wrapped in prayer shawls and phylacteries, with holy books strewn on the floor," Yehuda Meshi-Zahav, who heads Zaka, an emergency response group led by Orthodox Jews, told Israel Radio. Such sights I have never seen -- they recall dark days. U.S. Secretary of State John F. Kerry called Israeli Prime Minister Benjamin Netanyahu and expressed condolences for the attack. "This simply has no place in human behavior," Kerry told reporters in London. Netanyahu, who called top security officials to an emergency meeting, declared that the "despicable murderers" would not go unpunished. Within hours of the attack, a massive police contingent raided the family homes of the two assailants, identified as Udai Abu Jamal and Ghassan Abu Jamal, and Netanyahu later said the homes would be demolished and "inciters" held to account. A government statement said unspecified "additional decisions ... have been made in order to strengthen security throughout the country." Israel had already redeployed hundreds of troops to the West Bank after a pair of lethal stabbing attacks last week. In the wake of the latest attack, Israeli forces in east Jerusalem and several parts of the West Bank battled stone-throwing protesters, clashes that continued as night fell. A light-rail train passing through an Arab neighborhood of Jerusalem was pelted with rocks, forcing it out of service. At Kerry's prompting, Palestinian Authority President Mahmoud Abbas issued a denunciation of the attack, but coupled it with a call for a halt to Israeli "intrusions" on a site in the walled Old City revered by both Jews and Muslims. The militant Hamas movement, while not claiming any involvement in the attack, praised it. Celebratory gunfire rang out in the Hamas-dominated Gaza Strip and at several locations in the West Bank, and the group's spokesman Sam Abu Zuhri called the attack a response to the "continuing crimes of the occupation." The brutal nature of the attack, the shock of such a strike on a house of prayer, and the fact that the episode took place in a part of western Jerusalem considered far removed from recent clashes, boded ill for any calming of violence that that has roiled Jerusalem for months. We're at war. If every synagogue in the country needs protection, we have returned to bad times. - Aryeh Deri, Israeli lawmaker and resident of Har Nof Four people on the Israeli side have been killed in the past month in vehicular attacks by Palestinians, and in a spreading of "lone wolf" attacks outside the city, a soldier last week was fatally stabbed in Tel Aviv and a Jewish woman killed outside a West Bank settlement bloc. Much of the current burst of ill feeling is centered on the hilltop in the Old City revered by Jews as the Temple Mount and to Muslims as the Noble Sanctuary. Jews are allowed to visit the site but not pray there, and activists - some from within Netanyahu's government - have been calling for a change to that longstanding "status quo," infuriating Muslims across the Islamic world. Kerry visited Jordan - the formal custodian of the site - last week to try to ease frictions, winning pledges from both Netanyahu and Abbas in separate meetings for calming measures. But calls for moderation are likely to be lost in the outcry over the attack, and any retaliatory strikes arising from it. "We're at war," Israeli lawmaker Aryeh Deri, who comes from the neighborhood where the attack took place, told Israel radio. Neighbors and relatives of the attackers described them as heroes of the Palestinian cause. Palestinian media depicted the synagogue attack itself as retaliation, coming two days after an Arab bus driver was found hanged at a bus depot in the western part of Jerusalem. A forensic report ruled that there was no sign of foul play and that the death was a suicide, but Palestinian media reports sharply contested the impartiality of the examiners. Tuesday's assault was the most lethal in Jerusalem in six years, since a yeshiva on the city's outskirts was attacked by a gunman, killing eight of the religious students. An off-duty army officer killed that attacker. Special correspondent Maher Abukhater in Ramallah, West Bank contributed to this report. Follow @laurakingLAT for news out of the Middle East 8:20 a.m.: This post has been updated throughout with fresh details, Israel's vow of a tough response and a White House statement. 6:38 a.m. This post was updated with details from the Associated Press on the nationalities of the victims. 2:44 a.m.: This post has been updated with a statement from U.S. Secretary of State John F. Kerry. Nov. 18, 1:45 a.m.: This post has been updated with a statement from Palestinian Authority President Mahmoud Abbas. 11:45 p.m.: This post has been updated throughout with additional details and background.10:26 p.m.: This story has been updated throughout with additional details and background. This post was originally published at 10:14 p.m. Nov. 17