(Photo : ISHARA S. KODIKARA/AFP via Getty Images)
Four sailors in Sri Lanka have died after drinking from bottles they found at sea.

Four fishermen are dead and another two are in critical condition in Sri Lanka after drinking an uknown substance from bottles they found at sea.

The sailors were on a fishing trip 320 nautical miles from Tangalle, a town on the island's southern coast, when they spotted the bottles. 

According to the Sri Lanka Navy, the men drank from the bottles they believed contained alcohol. 

Susantha Kahawatte, the director general of the Sri Lankan Department of Fisheries and Aquatic Resources, told media outlets that the navy was working to bring sailors still on the ship quickly back to shore. The vessel Devon is being towed back to shore. 

In the interim, the sailors received medical care on the vessel as a precaution in case they couldn't reach land in time for immediate treatment 

Kahawatte said that the fishermen had distributed some of the bottles to other crews operating in the area, reported the BBC.  Efforts are being made to alert the other crews. 

The incident has sparked protests in the coastal town, with demands for speedy treatment of the sailors still at sea. 

Authorities are currently investigating the contents of the bottles.