A U.S. congressional panel has identified five countries including China, Russia and Ukraine, that it says lack legal protections for copyright.
Italy and Switzerland have made their first appearance on the Congressional International Anti-Piracy Caucus' annual watch list of copyright offenders.
"The lack of enforcement of intellectual property rights in these countries causes grave harm to American creators and to our economy as a whole," the report released on Thursday says.
Two nations that have been highlighted in past watch lists, Canada and Spain, have both taken "positive steps towards putting in place a stronger legal framework for the protection of copyright," the panel says.
World powers have been stepping up efforts to combat internet piracy but it remains a major issue. The Motion Picture Association of America claimed last year that had lost $58 billion and 373,000 jobs due to illegal downloading.
In Russia, "the lack of appropriate IP protection continues to allow for rampant Internet piracy affecting the global market," the report says.
"Existing laws fail to provide adequate protections for American intellectual property and enforcement against known rogue sites has been inadequate."
The panel highlighted in particular the "notorious" social networking site VKontakte, which offers music and film downloads.
Neighboring Ukraine was cited as "a hub for infringing content through peer-to-peer networks and hosted websites." The former Soviet republic is also "home to one of the world’s most notorious pirate markets, EX.ua," the report says.