It was announced on Friday that the Transportation Security Administration plans to extend the use of full body scanners to eleven additional airports in the United States over the next two years.

The American Civil Liberties Union immediately condemned the plan as a grave infringement on civil liberties.

The ACLU's Laura W. Murphy issued a statement warning of the risks in "these invasive search techniques" and suggesting that "It is far from clear whether this technology would have been able to foil the attempted Christmas Day attack and every resource we put into using these machines is a resource not spent on intelligence analysis or other law enforcement activity."

The potential of the scanners to infringe on individual freedoms was highlighted earlier this week when a Muslim woman was prevented from boarding a flight from England to Pakistan after she had been chosen at random to pass through a recently-installed scanner but refused to comply.

Muslims are concerned that the scanners, which provide a distinct though grainy outline of the passenger's genitals, violate Islamic prohibitions against being seen naked. The Fiqh Council of North America issued a fatwa against them in February.

"It is a violation of clear Islamic teachings that men or women be seen naked by other men and women," the fatwa states. "Islam highly emphasizes haya (modesty) and considers it part of faith. The Quran has commanded the believers, both men and women, to cover their private parts."

The Transportation Security Administration insists that "TSA's use of these technologies includes strong protections in place to safeguard passenger privacy. Screening images are automatically deleted, and the officer viewing the image will never see the passenger."

Muslims are not alone in their concerns, however. Orthodox Jews also consider the scanners "offensive, demeaning and far short of acceptable norms of modesty," although they do not technically violate Jewish law as long as the person viewing the scanner is of the same gender as the passenger. Conservative Christians have been debating the issue as well.