WASHINGTON (CNN) -- An embassy is a symbol of all the United States stands for, often making it an ideal terrorist target.

A pair of powerful explosions, said to be caused by car bombs and targeted at U.S. embassies, rocked the capitals of Kenya and Tanzania within 10 minutes of each other early Friday.

At least eight Americans are among the 65 or more who died at the U.S. embassy in Nairobi, Kenya. No Americans were reported killed in neighboring Tanzania, where five others are known dead, but the embassy building in Dar es Salaam was badly damaged.

The attacks conjure up images of Beirut in 1983, when a bombing at the U.S. Embassy killed 63 people. A subsequent attack on the U.S. Marine barracks that same year killed 241 people.

A survey at the time found that almost half of U.S. diplomatic facilities overseas were vulnerable to terrorist attacks. In response the government set new guidelines and spent millions on embassy security in the 1980s.

But experts say the location of the embassy building itself often invites or discourages a terrorist attack.

"Since the embassy in Nairobi is right in the middle of downtown, you can't very well protect against a bomb, a car bomb, that just drives up the main road downtown and blows up," said Robert Oakley, a former U.S. ambassador. "There is a similar situation in Dar es Salaam."

Protection for the 288 U.S. diplomatic facilities around the world is expensive and has been a hotly debated issue in Washington in recent years.

"The State Department budget gets cut so much that there is not enough money to provide for protection as well as other operations," Oakley said.

But other experts say that heightened security alone is not enough to deter future terrorist attacks.

"Ultimately it has to be complimented with such things as a good intelligence service. We need to know where the threats are," said Dr. Ernest Wilson of the University of Maryland.

CNN's Jeanne Meserve contributed to this report.