ATHENS, Greece -- Top anti-terrorist agents investigated three bomb blasts Wednesday that caused no injuries but rocked Greece's mission of trying to allay security fears for the Olympics that begin in 100 days.
Greek authorities said the explosions, which damaged a suburban police station, had no link to the Aug. 13-29 Olympics and were likely carried out by self-styled anarchists or other domestic extremists.
The timing of the blasts, however, offered multiple Olympic ties.
Wednesday began the 100-day countdown to the opening ceremony. A Greek delegation, led by the public order minister and the head of the Greek police, is in Washington for talks on how to safeguard the first summer Olympics since the Sept. 11, 2001, attacks on the United States.
On Monday, the IOC is to begin its final review of Athens' preparations, which have been beset by construction delays and other glitches.
Premier Costas Caramanlis called the bombing "an isolated incident which does not affect whatsoever the safety of the Olympic preparation."
Greece's anti-terrorist units took over the investigation. Police said foot patrols and other surveillance would be increased.
"I don't think panic is created by this kind of small incident," Athens Mayor Dora Bakoyianni said in Paris, where she was promoting the city.
But worries still loom despite organizers' security spending of more than $1.2 billion, including assistance from NATO.
"It's definitely got caught up in my head," said defending Olympic tennis gold medalist Venus Williams, who has said she is looking forward to competing in Athens.
"I'll just hope for the best and say my prayers - for everyone in general," she said from the German Open in Berlin.
U.S. pole vaulter Stacy Dragila said she's aware "there's a possibility of terrorist attacks. It is scary for the world at this time."
She added, however, that "I know that our governing body will not send us to a place that they don't feel is safe enough for us to go."
The U.S. Olympic Committee said its position has not changed.
"We have every expectation and every reason to believe our team will be in Athens for the games this August," USOC spokesman Darryl Seibel said.
The Athens organizing committee "is implementing a comprehensive security plan that will provide a safe and secure environment for athletes from every nation," he said.
Thomas Bach, a vice president of the International Olympic Committee, expressed the reality that exists at any large event: "We can only repeat openly that 100 percent security doesn't exist."
Australia - host of the 2000 Sydney Games - will "review the existing threat assessment," said its foreign minister, Alexander Downer. Australia is part of a seven-nation security advisory panel for Athens that includes the United States, Britain and France.
"These three bombings plunge us back into a problem that's important (and) troubling," France's Olympic Committee president, Henry Serandour, told France Info radio.
French President Jacques Chirac urged nations to "stand by" Greece, and British Prime Minister Tony Blair said "the games should go on as planned."
"This does not scare us at all," said Javier Valenzuela, a government spokesman in Spain, where 191 people died in terrorist bombings in March.
Israeli IOC member Alex Gilady said the games would not be deterred by the bombings or other threats.
"This is not a cause for panic," he said from Tel Aviv. "This sharpens everyone's attention. But I can't imagine any national Olympic Committee seriously considering not going to the games. I'm sure there will be 202 countries marching into the opening ceremony."
Last week, the IOC said it had taken out a $170 million insurance policy to protect against the Athens Games being called off because of war, terrorism or natural disasters. The unprecedented policy is to guarantee that the IOC and its affiliated bodies have enough money to continue operations in the event of a cancellation.
An anonymous caller to an Athens newspaper warned of the bombings about 10 minutes in advance. But there was no immediate claim of responsibility for the attacks, carried out with sticks of dynamite rigged with alarm clocks that exploded within a half-hour span in the suburb of Kalithea. The area is not near any key Olympic sites or hotels.
The bombs appeared intended to cause casualties despite the tip to the newspaper, police said. Parts of the building, which includes several police agencies, were damaged and windows were shattered in nearby apartments.
"This is something very serious," Kalithea Mayor Constantinos Askounis told Alpha radio. "It takes on a different dimension with the Olympics."
Anti-Olympic marches and other events have been staged in Athens, but violence is rare.
In February, a group using the names of the Olympic mascots, Phevos and Athena, claimed responsibility for firebombing two Environment Ministry trucks during IOC meetings in Athens.
Authorities said they crippled the most dangerous domestic terrorist threat with the convictions last year of 19 members of the group November 17, blamed for 23 killings and dozens of other attacks since 1975.
But smaller groups have continued to carry out bombings and arson attacks in Athens and other Greek cities. Most are against cars and commercial targets and rarely cause injuries.