On June 10, 2002 the child support reciprocity agreement between Norway and the U.S. became effective and Norway was declared a Foreign Reciprocating Country.
http://www.nav.no/English
Reciprocating Agreement with Norway
A Caseworker's Guide to Processing Cases with Foreign Reciprocating Countries
Norway - Addresses and Procedures (DCL-13-05) IRG - Contact Information An Overview of the Norwegian Child Support System 2012