The governor of the southern Japanese island of Okinawa has ordered a Defense Ministry branch to suspend all work at the site where a key U.S. military air base is to be relocated.

Gov. Takeshi Onaga said Monday that a concrete block thrown into the sea for a drilling survey of the reef at the designated site is believed to have damaged coral.

With the approval of Onaga's predecessor, the Defense Bureau last year began preparing the site for the eventual transfer of the U.S. Marine Corps Air Station Futenma. Many people on Okinawa want Futenma moved completely off the island.

Chief Cabinet Secretary Yoshihide Suga said the survey should proceed regardless of the governor's order.