A program that requires registration of foreign visitors from some countries in the Middle East and North Africa is being expanded to include men from Saudi Arabia, a U.S. ally and the home country of 15 of the 19 Sept. 11 hijackers.

An Immigration and Naturalization Service memo obtained by The Associated Press directs immigration inspectors registering aliens to include men, ages 16 to 45, from Saudi Arabia, Pakistan and Yemen, starting Oct. 1.

A Saudi foreign policy adviser, Adel Al-Jubeir, noted that nationals of other countries could also be subject to registration and Saudis were not being especially singled out.

The Justice Department already had begun registering visitors from Iran, Iraq, Sudan and Libya on the anniversary of the terrorist attacks. As part of the registration, the foreigners are required to provide fingerprints, photographs and details about plans in the United States.

"It is imperative that the officers remain vigilant and verify the age of all males from these three countries in order to identify properly those who are subject to special registration," says the Sept. 5 memo, sent by Johnny Williams, the INS' head of field operations.

The memo was sent to INS offices to explain how to implement the Justice Department policy known as the National Security Entry-Exit Registration System.

Justice Department spokeswoman Susan Dryden said she could not comment on the internal INS document. But, she said, "Saudi Arabia is an ally in the war on terrorism and they are not treated as state sponsors of terrorism in our enforcement efforts."

James Zogby, president of the Arab American Institute, said the registrations should be done at consulates, not at ports of entry where the process will create long waits and three lines -- one for citizens, one for non-citizens and one for Arab-Americans.

Registration is required on arrival to and departure from the United States. The foreigners also must be interviewed at an INS office for stays of more than 30 days and notify the INS within 10 days of any change of residence, employment or academic institution.

The memo says inspectors also can register visitors for national security reasons who they determine are worth monitoring. The memo says inspectors should consider whether the visitor has made an unexplained trip to Iran, Iraq, Libya, Sudan, Syria, North Korea, Cuba, Saudi Arabia, Afghanistan, Yemen, Egypt, Somalia, Pakistan, Indonesia or Malaysia or the visitor's explanation for the trip lacks credibility.

Among other things, inspectors will be told to consider registering foreign visitors who previously overstayed a U.S. visa or whose behavior, demeanor or answers indicate that the person may be a security threat, the memo says.

The additional scrutiny for Saudi nationals follows introduction of stricter rules for Saudis who apply for visas to the United States. The visa paperwork formerly handled by travel agents now requires interviews at consular offices. The scrutiny also comes as President Bush tries to build support for a U.S. attack on Iraq, for which Saudi Arabia has said it will not allow use of its territory unless the attack is under U.N. auspices.

Rep. George Gekas, R-Pa., chairman of the House Judiciary immigration subcommittee, said the registration program seeks to weed out people that Saudi Arabia and other countries are arresting and cracking down on.

"It's a natural extension of what is already occurring with respect to the war on terrorism, which is separate and apart from our relationships with the governments that are involved in this new round of alien registration," Gekas said.