The operator of Kazakhstan's giant offshore Kashagan oilfield denied reports of an oil spill near the field and said on Tuesday its facilities were working normally.
Globus, an ecological organization in the Central Asian nation, said earlier on Tuesday that satellite imagery had captured a large oil spill in the northern Caspian Sea near Kashagan.
Globus director Galina Chernova posted on Facebook that a slick of around 7 square km (2.7 square miles) had formed, citing images from Sentinel-1A, a European satellite.
But NCOC, largely owned by Western oil majors which operate the field, said those satellite images showed some different, natural phenomenon, and subsequent shots of the same location showed nothing unusual.
The company said it had studied the area and found no irregularities.
Kashagan, one of Kazakhstan's largest oil fields, is being developed by the North Caspian Operating Company (NCOC) consortium, which includes Shell, Eni, TotalEnergies and ExxonMobil.
The ecology department of Kazakhstan's Atyrau region, which borders the Caspian, has also said it would conduct a visual inspection and take samples at the oil production site.
(Reporting by Reuters; Editing by Kirsten Donovan and Josie Kao)