From AIN Online:

The customs preclearance facility the U.S. Customs and Border Protection (CBP) agency established last January at Abu Dhabi International Airport prohibited 450 people from boarding flights to the United States in its first year of operation. Some of those people were suspected terrorists, said Homeland Security Secretary Jeh Johnson, who wants to expand the network of preclearance facilities to other locations. The Department of Homeland Security (DHS), the CBP’s parent organization, now oversees 15 such facilities and has made customs preclearance “a big agenda item,” Johnson said in a speech to the Aero Club of Washington on January 16.