Ships searching in wind-whipped waters between South Korea and Japan have picked up at least 12 of the 22 crew members from a cargo ship that sank early Wednesday. Officials said only one of them remained conscious, but they did not immediately confirm any deaths.

South Korean and Japanese coast guard vessels and aircraft as well as two commercial cargo ships were continuing to search for the 10 missing crew members but the efforts were being slowed by strong winds and waves, South Korean officials said.

The 6,551-ton Jin Tian sank about three and a half hours after it sent a distress call at around 11:15 p.m. Tuesday in Japan's exclusive economic zone, Japanese coast guard spokesperson Shinya Kitahara said.

The vessel, which was Hong Kong registered and carrying lumber, sank about 160 kilometers (100 miles) southwest of Nagasaki, Japan, and about 150 kilometers (93 miles) south of South Korea’s Jeju island.

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The captain last communicated with the coast guard through a satellite phone around 2:41 a.m., saying crew members would abandon the ship, minutes before it sank, Jeju island coast guard officials said.

Six crew members were picked up by South Korean coast guard vessels, while a cargo ship picked up five and a Japanese Maritime Self-Defense Force vessel picked up one, according to Jeju’s coast guard.

According to South Korean and Japanese officials, 14 crew members are Chinese and eight are from Myanmar.

South Korean officials didn’t immediately confirm where the rescued crew members would be taken for treatment or whether the 11 who were unconscious were likely to survive their injuries if they weren’t already dead.

Japan’s Chief Cabinet Secretary Hirokazu Matsuno confirmed the rescue of at least five crew members, who he said were all Chinese nationals, but didn’t provide details about their health conditions.

Kitahara said the cause of the ship’s sinking was not immediately known and there were no signs that it collided with another vessel. He said the arrivals of Japanese patrol boats and aircraft were delayed by rough weather following the sinking.

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Officials at Jeju’s coast guard say a strong wind warning was issued for the area earlier on Wednesday but was later lifted. Winds were blowing at around 16 meters (yards) per second in the area as of 7 a.m., creating waves that were 3 to 4 meters (yards) high. The area’s water temperature was then around 18.5 degrees Celsius, the South Korean officials said.