Eighteen Ukrainian seamen were still missing more than 40 hours after their ship collided with a Chinese boat and sank in the waters near Lantau Island in the Hong Kong Special Administrative Region (HKSAR), a marine official said Monday.

Roger Tupper, Director of Marine of the HKSAR government, said rescuers were continuing with search efforts on sea surface near the site of the accident and that frogmen had dived and knocked on the capsized Ukrainian tugboat Neftegaz 67 in hopes of finding responses from sailors that may have been trapped inside its cabin.

"I am sorry to say, since we did the first dive yesterday morning, we have not had any response from within the hull of the vessel," Tupper told a press conference Monday afternoon, 43 hours after the two ships collided.

Tupper said the temperature near the site of the accident was about 19 degrees Celsius at the sea surface and 17 degrees underwater, adding that human beings "had the capability to survive 12 hours in medical terms" provided that they had air.

"Nevertheless, our operations are continuing. We are trying to find a way to access into the hull. We will continue with the work until we have retrieved the wreck and searched throughout the vessel to see if there is any of the 18 sailors," he said.

The collision occurred near the Brothers, an island group located between Tuen Mun and the Hong Kong International Airport, at around 9:30 p.m. (1330 GMT) Saturday when the tugboat collided with "Yao Hai," a 150-meter-long freighter registered on the Chinese mainland.

The Ukrainian tugboat, the smaller vessel, was heading towards an oil field in the South China Sea and carrying 24 Ukrainians and one Chinese on board when the accident occurred. Rescue teams saved 6 Ukrainian sailors and the Chinese soon afterwards.

The other 18 seamen were still missing and believed to be trapped inside the cabin of the 80-meter-long tugboat, which capsized at the seabed about 35 meters underwater.

Tupper said the Department of Marine were still investigating the cause of accident.

The frogmen had failed to find entry into the cabin of the sunken vessel. The salvage bureau of Guangzhou were considering sending a 4,000-ton ship to help remove the sunken tugboat to shallower waters so as to make diving efforts easier.

Ukrainian President Viktor Yushchenko has called on his government to support the Chinese rescuers and "provide medical aide and all that is needed for the Ukrainian sailors who have been rescued."

The Ukrainian Ambassador to China also appeared at the scene Monday and had been invited to observe rescue efforts, Tupper said.

(Xinhua News Agency March 25, 2008)