"A large number of them were out of status," Justice Department Spokesman Jorge Martinez told United Press International. "It is the duty and the responsibility of the INS to temporarily detain those who are found out of status."
The U.S. government has ordered the registration under the National Security Entry Exit Registration System. Launched on the first anniversary of the Sept. 11, 2001, attacks, the program requires the U.S. government to maintain photographs and fingerprints of all male visitors from Iraq, Iran, Libya, Syria and Sudan. An additional 13 countries were added to the list in October.
More than 3,000 men ages 16 and older from the five countries needed to register by Monday evening.
Another group of more than 7,000 males from 13 other nations -- Afghanistan, Algeria, Bahrain, Eritrea, Lebanon, Morocco, Oman, Qatar, Somalia, Tunisia, United Arab Emirates, Yemen and North Korea -- are required to register by Jan. 10.
Pakistan and Saudi Arabia were added to the list earlier this week. Citizens of both nations visiting the United States must register with the INS between Jan. 13 and Feb. 21.
Martinez said the INS will continue to hold out-of-status aliens for national security checks and "unless the check turns up anything negative, we will also continue to release them."
Notable deaths of 2014 [PHOTOS]