The Bush administration says some 28 groups around the world - including Osama Bin Laden's al-Qaida organization - are involved in terrorism, a finding that allows Congress to keep sanctions against them in place - and makes it illegal for Americans to contribute money. But supporters of Osama bin Laden managed to evade some of these restrictions prior to last month's terror attacks.

Most of the same groups that have been on this list are still on it. But what is noteworthy is that one group, al-Qaida, had a network of followers here in the United States alleged to have been involved in last month's terror attacks - despite sanctions that should have kept known terrorist supporters out of the country. Al-Qaida has been on the terrorist list since 1999.

At least one alleged al-Qaida supporter, Mohammad Atta, the Egyptian believed to have been aboard one of the commercial airliners that crashed into the World Trade Center, even managed to leave and return to this country without apparent detection. By law, any group on this list is supposed to have its assets frozen and its members denied U.S. visas. Authorities continue to investigate whether those involved in the terrorist attacks used false or stolen passports.

At the State Department, Spokesman Richard Boucher came close to saying government efforts to detect members of the al-Qaida network and keep them out of the country all but failed.

"If we don't have information when someone applies, then we don't get a hit when we check the name against the database," Mr. Boucher explained. "So the issue that we are looking at most closely right now is how to make sure that the best possible information gets into our databases."

The State Department is required to notify Congress every two years which organizations it considers to be terrorist groups so that sanctions preventing them from raising money in this country can be extended.

In all, 28 groups are on the list. Dropped are the Japanese Red Army and Peru's Tupac Amaru rebels. Secretary of State Colin Powell determined both to be no longer active.