Firefighters were working to bring under control a massive fire at Philadelphia Energy Solutions Inc' refinery on Friday, according to Philadelphia city officials and company sources.

The blaze has resulted in damage that could keep the affected unit shut for an extended period, they said.

Gasoil stocks in independent storage in the Amsterdam-Rotterdam-Antwerp (ARA) refining and storage hub fell by 6pc in the week to Thursday, data from Dutch consultancy Insights Global showed.

Libya's 120,000 barrel per day Zawiya oil refinery is currently running at around half capacity due to high demand on the local electricity grid during the summer season, a Libyan oil source told Reuters.

A spokesman for the plant said the situation at the refinery was stable, but sometimes production can fall due to routine operational issues or circumstances beyond the company's control.

Russian pipeline monopoly Transneft said on Thursday that more contaminated oil had been found at a section of the Druzhba pipeline from Belarus to Poland, the RBC media portal said.