ASTANA, July 3 (Reuters) - The Atyrau oil refinery in western Kazakhstan was completely halted on Monday due to power outage, a refinery official told Reuters.

The outage caused an emergency halt at the refinery and power is yet to be restored, the official said.

Separately, Kazakh news website Zakon.kz reported that an emergency outage occurred at the Mangystau plant which also supplies power to the country's largest oilfields such as Tengiz and Kashagan. (Reporting by Tamara Vaal Writing by Olzhas Auyezov Editing by Mark Potter)