The North may be preparing to test-fire another long-range missile - possibly toward Hawaii. And American warships are tracking a North Korean cargo vessel that could be carrying banned weapons, reports CBS News correspondent David Martin at the Pentagon.
The cargo ship Kang Nam may not look like much, but it is suddenly attracting a lot of attention from the U.S. military.
It is the first North Korean ship to set sail since the U.N. Security Council passed a resolution calling on the U.S. and other navies to intercept North Korean vessels believed to be carrying arms.
That means a U.S. warship could request permission to search the Kang Nam, but it could not use force to board her if North Korea refuses, which it almost certainly will.
North Korea has threatened to retaliate if its ships are interfered with - and is preparing a new launch pad to fire off a long range missile capable of reaching Hawaii. Two previous long-range missile tests have failed, but the Pentagon is taking no chances.
It's positioning a giant radar at sea to track any North Korea launch and sending interceptor missiles to Hawaii as a back up to interceptors based in California and Alaska.
"I think we are in a good position, should it become necessary to protect the … American territory," Defense Secretary Robert Gates told reporters.
The Kang Nam was halted for safety violations entering the port of Hong Kong two years ago. That such a seemingly unassuming vessel could become a key player in such a high-tech standoff is almost laughable.
Except that that is exactly what's happening.