A Saudi Arabian tanker broke in two Friday and its stern section sank after a mystery blast believed to have been caused by a drifting mine left six crewmen dead, authorities said.

Shipping executives said the Greek captain of the 36,904-ton Sagheera was among those killed in the explosion in the southern end of the gulf Thursday. Two other men were listed as missing.They said 26 members of the crew made up of Greek officers and Sri Lankan seamen were rescued Thursday from lifeboats by the Omani Coast Guard.

The Sagheera was ripped by an explosion as it was sailing empty into the Strait of Hormuz, en route for the Saudi port of Mina Saud. The blast started a fire.