WASHINGTON (AP) -- The National Ice Center issued a warning Tuesday that an iceberg almost the size of Rhode Island threatens shipping in the ocean between South America and Antarctica.

The iceberg, named B-10A, measures 24 by 48 miles and is in the shipping lanes in the vicinity of latitude 58 degrees, 36 minutes South, longitude 57 degrees West.

The iceberg is drifting southeast at about 7 to 9 miles per day, and smaller icebergs are breaking off as it moves into relatively warmer water. A cautionary zone has been established 165 miles in radius around the berg, the ice center reported.

The ice center has been tracking the parent iceberg, B-10, since January 1992. In the summer of 1995 it broke into two pieces, the larger of which became B-10A. The smaller iceberg drifted west in and along the Antarctic ice pack and eventually became too small to warrant tracking.

The Suitland, Md.-based National Ice Center provides worldwide operational sea ice analyses. It is operated by the Navy, the National Oceanic and Atmospheric Administration and the Coast Guard.