Malaysians feared the worst when a bomb threat triggered the morning evacuation of thousands of people from the world's tallest buildings the Petronas Twin Towers in Kuala Lumpur. A second threat cleared another skyscraper that houses offices for IBM and Standard Chartered Bank in Malaysia's biggest city.
Police later ruled both threats a prank but another chill was cast when the U.S. Embassy in Jakarta warned that terrorists may be planning a strike against American interests in Indonesia.
As the world recoiled, global leaders raced to prevent a possible repeat of the death and destruction unleashed when two hijacked airplanes crashed into New York's World Trade Center on Tuesday, destroying both towers and likely killing thousands of people.
It was a shock felt round the world.
"What about my country, or here in Tokyo? Will there be attacks as well?" said British headhunter Nick Frank, pouring over a Japanese newspaper with the banner headline, "America Center of Simultaneous Terror."
Across the globe, soldiers mobilized, embassies locked their doors and stock markets shut down. Schools kept students home, and skyscrapers cut off access. Leaders mourned, rushed home from abroad and hastily called crisis meetings.
Japanese Prime Minster Junichiro Koizumi on Wednesday said he supported the United States' position of not yielding to acts of terror.
"We can't overlook terrorist acts," he told reporters when asked if he would support possible retaliation by the United States after suicide attacks by aircraft hijackers on New York City's signature World Trade Center and the Pentagon.
"Justifying terrorism can't be allowed by the international community. I think it is appropriate that (U.S. President George W.) Bush is taking the stance of finding the culprits and taking decisive action against them."
That was cold comfort, however, on the streets of Tokyo, where a wary population still remembers the 1995 nerve gas attack on Tokyo's subway system that killed 12 people and sickened thousands.
Another terrorist attack "could happen in Japan, too, since we're allies with America," bus driver Kohei Suzuki said.
Wednesday's terrorist warning in Indonesia followed a similar alert issued last week by the U.S. State Department to Americans living in Japan and neighboring South Korea. At the time, an embassy spokesman in Tokyo said officials had "credible" information an attack might occur in the region. So far, it hasn't.
But Tuesday's attacks in the United States underlined the need for everybody to be prepared.
"The challenge is how to protect the nation," Japan's Defense Agency chief, Gen Nakatani, said, according to Kyodo news agency, after cutting short an Indonesian visit to returhome.
Around the world, countries mobilized soldiers or police to bolster security at potential terrorist targets government buildings, airports, harbors, diplomatic missions and military bases.
"It's better to have too high security level than too low," Danish Prime Minister Poul Nyrup Rasmussen said.
British Prime Minister Tony Blair led a crisis meeting of senior security officials, and European Union officials were to do the same in Brussels, Belgium. NATO ambassadors also met, after telling much of the alliance's office staff to stay home as a precaution.
Traveling European Commission officials were called home immediately, some from as far away as Singapore.
At the same time, the European Central Bank gave an emergency injection of liquidity into monetary markets, meant to stabilize volatile financial swings.
Britain's Scotland Yard said it marshaled 1,000 extra police for London's streets, just to "reassure the public."
Israel sealed its land borders with Jordan and Egypt until further notice. Officials said the border crossings were shut late on Tuesday and they were not sure when they would reopen.
The spokesman said foreign airlines could apply for special permission to fly from Israel's Ben Gurion international airport despite a ban imposed on Tuesday on all foreign flights taking off and landing at the airport.
Israel's national carrier El Al was continuing flights abroad with the exception of the United States, where airports are still closed. A port spokesman said shipping ports were still operating but that ships had been given specific security instructions.
In a rare afternoon television address, Taiwanese President Chen Shui-bian urged the public to stay calm, saying the island must "stick together when facing a possible change in the international situation."
Throughout Asia, black-clad swat teams and soldiers with bomb-sniffing dogs patrolled government buildings, airports and embassy neighborhoods.
International schools in Moscow, Bangkok, Jakarta and Tokyo canceled classes Wednesday.
Worry also ran high that other high-rises not just the World Trade Center and the Petronas Towers could be marked for attack.
Check points were set up outside Hong Kong's Citibank Tower and Asian-Pacific Financial Tower, and the CN Tower in Toronto, Canada, was completely shut following Tuesday's strike.
In an effort to calm financial markets, which tumbled after the terrorist attacks, the Tokyo exchange opened 30 minutes late and established narrower trading bands. Still, the benchmark Nikkei index plummeted more than 6 percent to its lowest level since 1984.
Markets in Taiwan, Malaysia, Thailand and Cyprus were closed completely.
Tuesday's airstrike on the World Trade Center was the most devastating terrorist onslaught ever waged against the United States. The deadly calamity was witnessed on televisions across the world as another plane slammed into the Pentagon, and a furth crashed outside Pittsburgh.
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