TOKYO  —  Japan's (search) Coast Guard dispatched aircraft Sunday to survey a 3,300-foot-high column of steam rising from the Pacific Ocean off a small Japanese island, in a possible sign of an undersea volcanic eruption, officials said.

The water vapor resembling a huge cloud, was seen from the island of Iwo Jima (search) on Saturday by Japanese troops stationed there, said Hiroshi Shirai, a spokesman for the Maritime Self-Defense Forces.

Several soldiers witnessed the vapor in waters roughly 30 miles southeast of the island, he said. The defense officials who later conducted an aerial survey from a rescue helicopter also found the surface of the water in the area turning red, Shirai said, adding that there might have been an underwater volcanic activity.

On Sunday, Japan's Coast Guard sent aircraft to the area to conduct a more thorough survey in daylight. Coast Guard officials said officials are still trying to find out what exactly has occurred in the waters, and no further details were immediately available.

The Meteorological Agency said there was no danger of tsunami, which can be caused by undersea seismic activity or landslides. Iwo Jima is about 700 miles southeast of Tokyo.