WASHINGTON (Reuters) - 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, US President Barack Obama told CBS in an interview that aired on Tuesday (April 26).

"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," Mr Obama said.