The European Central Bank may raise interest rates to preserve credibility in the face of a war-driven rise in fuel costs but there is little to suggest yet that high inflation is taking root in the euro area, ECB policymaker Olli Rehn said in an interview. The ECB is all but certain to increase borrowing costs at its next meeting on June 11 after disruptions to the Strait of Hormuz caused a spike in oil prices and pushed inflation in the euro area well above the bank's 2% target.