ABOARD JINGGANGSHAN, March 13 -- Under clear sky, Chinese naval vessel Jinggangshan is plowing waters in the Gulf of Thailand in search of missing Malaysia Airlines Flight MH370.

The amphibious landing ship is just one of the dozens of Chinese and foreign vessels scouring the area for the ill-fated Boeing 777 aircraft, which suddenly vanished from radar early Saturday morning with 239 people on board.

With 154 of the 227 passengers being Chinese, Beijing has launched an all-out search and rescue mission, with eight vessels scouring waters around MH370's last confirmed location and 10 satellites providing technological support in the space.

Since cruising into position Tuesday, Jinggangshan has been working round the clock with all its monitoring systems activated, including radar, infra-red and optoelectronic searching devices. Two helicopters aboard the vessel also carried out air search.

On Wednesday, the weather at the target sea area was good and thus offered high visibility.

At 3:30 p.m. Beijing time (0730 GMT), a suspicious oil slick was sighted from the port side of Jinggangshan.

The ship slowed down and veered to the slick. It turned out to be just another disappointment. The 600-meter-long and 3- to 5-meter-wide slick was a discharge from other ships within 24 hours.

By 9 p.m. (1300 GMT), no solid clues were located.

As of 6 p.m. (1000 GMT) Wednesday, Chinese search teams had searched 23,282 square km of waters; on Thursday they will cover 19,768 square km, according to the China Maritime Search and Rescue Center.

"Generally speaking, once an area is locked, the search scope at sea will be gradually narrowed down," said Lian Jianli, deputy head of the command post for the Chinese navy's maritime search operations.

But due to the effect of winds and ocean currents, the search area for this special operation is likely to be further expanded if no clues are found in the next few days, he added.

Lian said that the Chinese navy, taking into consideration the advantages and disadvantages of each search method, has employed nearly all its means to hunt the missing plane.

No matter how complicated and arduous the mission is, Chinese rescuers have vowed, they will not give up.