Even for North American Jews used to thinking about security issues at home -- and confronting terrorist acts in Israel -- the series of horrific acts that struck Tuesday came as a devastating, unimaginable blow.
"This is surreal. This whole situation seems surreal," said Martin Raffel, the associate executive vice chair of the Jewish Council for Public Affairs, whose offices are located in midtown New York, a safe distance from the destroyed World Trade Center.
Before the initial shock wore off from the hijacked plane attacks on the World Trade Center in New York and the Pentagon near Washington, Israel was offering help, U.S. Jewish groups were reacting with anger and Jewish communities across North America were holding prayer vigils.
Fire raged and smoke billowed around the towers after the two attacks, which occurred around 9 a.m. Tuesday.
The two towers collapsed by mid-morning, wreaking more havoc, claiming even more victims and hampering rescue efforts.
Reports said that more than 250 passengers were on board the four hijacked planes at the center of the day's horrific events -- two hit the World Trade Center, one hit the Pentagon and one crashed in western Pennsylvania -- but at press time, there were no reliable reports of the number killed or injured.
However, New York officials estimated that there could be thousands of casualties from the World Trade Center explosions alone.
The attack was described as the worst on American soil since the Japanese assault on Pearl Harbor. By comparison, 2,400 people were killed on that day -- Dec. 7, 1941 -- which President Roosevelt described as a "date which will live in infamy."
Speaking Tuesday morning, President Bush described the crashes as an "apparent act of terrorism" and vowed to use the "full resources" of the U.S. government to "hunt down and find those folks who committed this act."
Two Jewish groups are housed near the site of the New York attacks, but efforts Tuesday to reach Agudath Israel of America and the Orthodox Union were unsuccessful.
The Educational Alliance, a Jewish-run community center in downtown New York, treated people suffering from light injuries and shock.
"People were wandering in the streets coming from the World Trade Center, disoriented," said Ben Rodriguez, director of administration services for the Educational Alliance.
"People were streaming in for a few hours," he said, but by late afternoon, things had quieted down.
Some Jewish groups in New York, including the Conference of Presidents of Major American Jewish Organizations and the United Jewish Communities, evacuated their offices as part of building-wide evacuations.
Jewish and non-Jewish businesses and facilities were closed in various cities across the United States, from Philadelphia to San Francisco, in fear of further attacks.
The UJC promised to resume business as soon as possible.
"This has been a tragic day for our country," the UJC said in a statement. "We express our condolences to the families of the individuals who lost their lives."
Israel, which closed Ben-Gurion Airport to foreign planes, evacuated all its diplomatic missions around the world. In an ironic turnabout, some Israelis were scheduled to hold a solidarity rally with the American terror victims on Tuesday night.
Prime Minister Ariel Sharon declared a state of mourning in Israel on Wednesday, and said the terror attacks would prove "a turning point in the war against terrorism."
President Moshe Katsav conveyed to Bush Israel's "deep sorrow," and the Health Ministry launched a blood drive.
"All of us in Israel embrace you, would like to express our condolences, and add our best wishes for a speedy recovery to those who have been injured," Katsav said. "Everything must be done to defeat this phenomenon in which insane people will stop at nothing to disrupt daily life."
Defense Minister Benjamin Ben-Eliezer approved the dispatch of rescue units to the United States. He also canceled a visit to Washington that was planned for later in the week.
Palestinian Authority President Yasser Arafat sent the "condolences of the Palestinian people to American President Bush," but many of his people did not seem to share Arafat's remorse.
Thousands of Palestinians celebrated the attack throughout the West Bank, chanting "God is great" and distributing candy. In Palestinian refugee camps in Lebanon, gunmen fired into the air in celebration.
In Argentina -- where two Jewish institutions were hit by bombs in the 1990s -- authorities pledged to increase security at Jewish sites. In Berlin, the Parliament was evacuated and the Jewish Museum was closed, just two days after it officially opened.
American Jewish groups strongly condemned the attack and "pledged to double check already tight security," in the words of one Jewish spokesman who asked not to be identified.
"We are outraged and unequivocally condemn today's terrorist acts against the United States," the American Israel Public Affairs Committee said in a statement that was echoed by other groups.
Abraham Foxman, national director of the Anti-Defamation League, said Tuesday's events would force the United States to step into Israel's shoes.
"My feeling is that the American government has always understood Israel's dilemma" in fighting terrorism, but "now America, too, will have to struggle with, 'How do you respond, how do you prevent' " this kind of thing, Foxman said.
Though no direct links have been established between the attacks and U.S. support for Israel, some worried about that prospect.
"Will the blame be placed on Israel? Will the blame be placed on the fact of American support?" wondered Foxman, who along with thousands of others across the country was stranded at an airport when the attacks occurred.
"The United States has been brutally attacked today, and we must consider that our nation is at war," David Harris, the executive director of the American Jewish Committee, said in a statement.
But exactly who would be the target of that war remained unclear.
Spokesman for several radical Palestinian groups denied reports that they were behind the attacks. Speculation focused on Osama bin Laden, but there was no initial evidence linking the Saudi terrorist mastermind to the attacks.
Manhattan Jews were horrified by what had happened -- and impassioned about how America ought to react.
It's outrageous that America "has been brought to its knees by terrorists," said Larry Kowlowitz, vice president of PK Furriers in midtown Manhattan. "It's time for the dog to wag the tail, not for the tail to wag the dog. We should use our muscle and make these smaller nations understand that we have the power. Like the Bible says, 'An eye for an eye.' Even if innocent people are killed."
Anger was only part of the Jewish response, however; others began attempts at prayer and healing.
In New York -- and elsewhere in North America, from L.A. to Montreal -- prayer vigils were scheduled to be held as early as Tuesday evening.
"Our community felt the need to get together for spiritual reasons," said Mark Finkelstein, director of the Jewish Community Relations Council of Des Moines, Iowa.
The United Synagogue for Conservative Judaism said it would send out a special packet of prayers for its congregations.
Congregation B'nai Jeshurun in Manhattan urged its members to donate blood and provide shelter for victims of the attacks.
Meanwhile, the attacks caused the cancellation of a major pro-Israel solidarity rally planned for Sept. 23 in New York.