The rules went into effect Tuesday and call for the inclusion of several security measures to protect passport holders from data theft, according to the agency. One method will prevent data on the built-in radio frequency identification tag from being "skimmed," or captured from afar by using a special material on the passport cover that blocks the data from being read by unauthorized equipment.

In August, the State Department announced that the electronic passport program will begin in December for government workers who have "official" or "diplomatic" passports, and will be fully rolled out by next October for all U.S. citizens.

The use of electronic passports is designed to enhance document and border security and to make identification for international travel easier and more secure for U.S. citizens, the department said.

During a public comment period earlier this year, the agency received 2,335 messages, with more than 2,000 of them from critics concerned about data integrity, data theft and privacy.

Officials at several privacy groups could not be reached for comment early Thursday.