North Korea warns that U.S. bases in Guam, Japan are within range

Updated 8:41 PM EDT, Thu March 21, 2013

Story highlights

North Korea is verbally "firing back" at recent moves by the U.S., an analyst says

Pyongyang has expressed anger that the U.S. is flying B-52s over South Korea

The flights are part of annual military exercises

Tensions on the Korean Peninsula have flared since the North'