The United States says it is closely watching several North Korean ships suspected of carrying weapons of mass destruction.

Press Secretary Geoff Morrell of the U.S. Defense Department told reporters Wednesday that although the U.S. continues to follow a North Korean cargo ship currently in the South China Sea, the U.S. military is interested in multiple North Korean vessels.

But he stopped short of elaborating on the extent to which other ships from the North were being monitored.

The U.S. military has been shadowing the North Korean cargo ship, the Kang Nam, since it left a North Korean port early last week. The U.S. suspects the two-thousand-ton Kang Nam is bound for Myanmar.

Asked about when the Kang Nam could be interdicted, Morrell said no decision on the matter has been made, adding that he does not believe a decision is imminent.