Royal Dutch Shell PLC (RDSB.LN) said Tuesday that Shell companies are assisting the European Commission in an enquiry into trading activities.

"We are fully cooperating with the investigation. For legal reasons we cannot make any further comment at this stage," Shell said in a statement.

The European Union has announced anti-trust raids in oil and biofuel sectors that took place May 14. It said it raided oil and biofuel companies in two member states on anti-trust concerns.

Norway 's Statoil ASA (STO) said it was also inspected as part of the raids.