The United States says it is confident that it will be able to use its bases in Japan in the event of an emergency on the Korean Peninsula.

Assistant Secretary of Defense for Asian and Pacific Security Affairs Wallace Gregson told a House Armed Services Committee hearing Tuesday that the U.S. is absolutely confident it would be able to use its Japanese bases in response to a North Korean threat.

Gregson was asked if he thought Japan would allow the U.S. to use American bases to undertake an action that the Chinese disapproved of.

Gregson also said that he has no doubt Japan is fully aware of the threat from North Korea and is fully supportive of all the provisions of the U.S.-Japan alliance treaty.

His comments come as the relocation of a U.S. airbase on the southern Japanese island of Okinawa is emerging as a key controversy in Japan. A growing number of people in Japan are calling for the removal of U.S. troops from the island.

Gregson noted that the U.S. is continuing to make utmost efforts to trace North Korean weapons sales and that the sinking of the Cheonan has reminded the U.S., South Korea and Japan how dangerous of a neighbor North Korea is.