Rescue divers in Hong Kong have recovered a third body from a sunken Ukrainian tugboat but 15 Ukrainian sailors are still missing in a recovery operation hampered by swift ocean currents and poor visibility, according to Reuters.

"The body was located inside a cabin on the main deck of the shipwreck," said Eric Ng, a spokesman for Hong Kong`s Fire Services Department.

The Ukraine-registered tugboat Neftegaz-67 sank on Saturday and hopes have all but faded that survivors might yet be found within air pockets in the overturned vessel.

The ship sank after colliding with a large Chinese bulk carrier and is now lying on the seabed 37-metres (122 feet) under water.

Of the tugboat`s 25 crew, seven members including six Ukrainians and one Chinese were rescued soon after the disaster.

A team of divers had by Friday afternoon carried out more than 50 dives down to the tug, but the recovery operation has been painstakingly slow and hazardous at times, with frogmen trapped by debris and hampered by swift currents.

Authorities plan to soon deploy one of Asia`s largest salvage ships from China to drag the tug off the ocean floor, but officials say this complex process could still take 7-10 days.