GOTO, Nagasaki --
An unidentified white cylinder some 25 meters long has been found drifting in the sea off an island here, coast guard officials said.

The plastic-coated steel cylinder, which measures three to four meters in diameter and is marked "Nitrogen-filled," "Warning" and "Vacuum" in both Chinese and English, was first spotted by a fishing boat that was sailing in the area.

The Nagasaki Coast Guard Office is trying to identify the cylinder, and believe it may have been accidentally dropped from a large vessel that was transporting machine parts.

"If the object had contained something like liquid nitrogen, as indicated on its surface, it should have dissipated and there's little danger," said a coast guard office representative.

Officials have attached lights to the cylinder and are alerting fishermen to its presence. They have also been asking the Chinese consulate general and other entities to provide information on the owner of the object.

As of 4 p.m. on Thursday, the cylinder was drifting in the East China Sea, about 30 kilometers north of Fukue Island in Goto. The island is part of the Goto Archipelago.