SEOUL: A sailor died and eight were missing Saturday after their fishing boat, which had been helping search for missing sailors from a sunken warship, collided with a freighter, maritime police said.

Meanwhile, navy divers managed to reach the sunken warship's hull sections but were unable to find any of the 46 missing sailors from the 1,200-tonne corvette, a military spokesman said.

The warship went down on March 26 following a mystery explosion near the disputed maritime border with North Korea.

South Korea's navy, backed by fishing boats and US military divers, was struggling against high waves and strong currents to explore the hull sections of the sunken warship where many of the missing sailors could have been trapped.

The Joint Chiefs of Staff spokesman said the divers on Saturday groped their way into the entrance of the dining hall of the ship but it was filled with water.

Other divers examined the captain's chamber and the communications centre in the broken wreckage of the sunken corvette.

"But no missing sailors have been found," the spokesman told AFP.

Divers' attempts to go deeper inside the hull were being hampered by wires and debris detached from the ceiling and walls, he said.

On top of this tragedy, a fishing vessel with nine crew aboard sank after sending a distress signal late Friday after it was apparently hit by a Cambodian-registered ship.

"We've captured the Taiyo 1, a Cambodian-registered 1,472-ton freighter, which was apparently involved in the collision," an Incheon Maritime Police spokesman told AFP.

The boat was one of 10 trawlers helping with the search for the missing sailors.

Fifty-eight crewmen were saved soon after the sinking, but none since. Officials suspect most of the missing are in the rear section of the hull.

No one has officially declared the missing sailors to be dead, even though the air in any watertight compartments would likely have been used up.

The area has been crowded with ships and aircraft, which have been combing the area in a search and rescue operation.

The disaster site is close to the disputed border which was the scene of deadly naval clashes between North and South Korea in 1999 and 2002 and of a firefight last November.