(Adds background, confirmation of time start)
ROSA KHUTOR, Russia Feb 16 (Reuters) - The Olympic biathlon men's 15km mass start at the Sochi Winter Games has been postponed until Monday due to poor visibility after heavy fog fell on the Laura centre, organisers said on Sunday.
Organisers initially said the race would start at 1030 local time (0630 GMT/01:30 AM ET), though updated that information later to say it would start at 1000.
The International Biathlon Union (IBU) said in a statement: "The postponement was due to fog not only in the stadium but also due to heavy fog on the tracks which created dangerous conditions."
It later confirmed the 1000 start.
The race was first delayed by one hour from 1900 to 2000 local time but conditions did not improve.
In biathlon, athletes have to complete a distance over skis and stop at a shooting range two or four times depending on the disciplines.
The targets are 50 metres from where athletes stand or lie and were impossible to see on Sunday.
It was the third time that a biathlon race at the Olympics has been postponed.
At the Nagano Games in 1998, the men's sprint was called off after heavy snow and fog forced the race to be stopped and be started again the following day.