U.S. citizens are subject to the laws of foreign countries. Furthermore, some laws are prosecutable in the United States regardless of local law.
Under the Prosecutorial Remedies and Other Tools to End the Exploitation of Children Today Act of 2003 (PROTECT Act), it is a crime, prosecutable in the United States, for a U.S. citizen or lawful permanent resident to engage in illicit sexual conduct in a foreign country with a person under the age of 18, whether or not the U.S. citizen or lawful permanent resident intended to engage in such illicit sexual conduct prior to going abroad.
Under the Protection of Children from Sexual Predators Act of 1998, it is a crime to use the mail or any facility or means of interstate or foreign commerce to transmit information about a minor under the age of 16 with the intent to entice, encourage, offer, or solicit any person to engage in any criminal sexual activity, among other things, the production of child pornography.
For additional information on federal laws related to crimes against minors overseas, please see the U.S. Department of Justice (DOJ)’s Child Exploitation and Obscenity Section.
If you want to report a crime, please contact the FBI or see numbers provided by DOJ here.