The United States is preparing to defend itself against North Korea, positioning its missile development systems and setting up a "shield" to counter low-level threats from an "erratic" country, U.S. President Barack Obama told CBS in an interview that aired on Tuesday.

RELATED: US pledges 'strong response' to another North Korean nuclear test

"One of the things that we have been doing is spending a lot more time positioning our missile development systems, so that even as we try to resolve the underlying problem of nuclear development inside of North Korea, we're also setting up a shield that can at least block the relatively low-level threats that they're posing now," Obama said.