Oil output at Kazakhstan’s Kashagan Field reached an all-time high of 400,000 barrels per day (bbl/d) on June 4, three sources familiar with daily production data told Reuters.

Output has risen after a successful completion of maintenance on the oil field in May.

Prior to the maintenance, daily oil production on Kashagan oil field was at 330,000-340,000 bbl/d.

North Caspian Oil Co. (NCOC), Kashagan’s project operator, and the Kazakhstan Energy Ministry did not immediately respond to requests for comment.