(Adds detail about blackouts in Bosnia, statement from Croatia's HEP, reports from Croatian and Albanian TV stations, in paragraphs 3-8)
BELGRADE, June 21 (Reuters) - Montenegro, Bosnia and most of Croatia's Adriatic coast where temperatures approached 104 degrees Fahrenheit (40°C), experienced a major power blackout on Friday, according to Montenegro power distributor CEDIS and local media.
"Almost the entire area of Montenegro is without power due to network outages," CEDIS said on its Facebook page.
A Reuters reporter said the capital Sarajevo and the cities of Banja Luka and Mostar were without electricity. Local media reported a blackout across the country.
Croatia's HEP power utility said that the outage in parts of the country had been caused by "an international disturbance that affected several countries".
"The Croatian transmission system operator is conducting an analysis with the system operators of neighbouring countries to determine the cause."
HEP said it had put its production capacities into full operation to ensure "supply in the shortest possible time".
Most of Croatia's Adriatic coast was without electricity, state TV HRT reported. It said the traffic in the coastal city of Split had come to halt after traffic lights stopped working. Sirens of ambulances could be heard throughout the city, it said.
Albanian TV broadcaster Top Channel said a number of towns including the capital Tirana were out of electricity. It quoted sources as saying that the malfunction of an interconnector in Montenegro had caused the blackout. (Reporting by Aleksandar Vasovic; editing by Jason Neely)
