LONDON, Nov 6 (Reuters) - Russian oil major Lukoil's

Volgograd refinery has halted operations after it was

struck by Ukrainian drones, three sources familiar with the

matter said on Thursday.

They said that the primary processing unit, CDU-5, with a

daily capacity of 9,100 metric tons, or 66,700 barrels per day -

a fifth of the plant's total capability - and a hydrocracker

with a capacity of 11,000 tons per day were damaged during the

attack.

Lukoil did not respond to a request for comment.