An important mission of U.S. Customs and Border Protection (CBP), a branch of the Department of Homeland Security, is to detect and seize merchandise entering the United States that violates existing IPR.  Once you have recorded your trademark or copyright with the PTO or Copyright Office, you should consider taking the next step: register it with the CBP.   Trademarks and copyrights may be recorded for $190.00 each.  Customs enters the recordation into a centralized database accessible by all field offices.   Customs will detain or seize merchandise that is counterfeit, confusingly similar, or possible pirated material.  It will notify the IPR owner about the right to pursue enforcement actions.  Customs also has the right to pursue such actions on its own. 

The system is a little different for patents.  Patents are not recordable with CBP because import infringement issues are under the jurisdiction of the U.S. International Trade Commission (ITC).  Suspected infringement cases are taken to the ITC, which issues an exclusion order if there is a proven violation.  Customs will then enforce the exclusion order.  

For more information on Customs enforcement, visit: http://www.cbp.gov/xp/cgov/import/commercial_enforcement/ipr/.