Elevated price pressures stemming from pandemic-related disruptions are persisting longer than anticipated, Federal Reserve chair Jay Powell will tell US lawmakers at a joint congressional hearing with Treasury secretary Janet Yellen on Tuesday.

In testimony to be delivered to the Senate banking committee at 10am Eastern Time, Powell acknowledged the economy was getting stronger, but warned of the risk that inflation could stay higher for longer than anticipated as the more contagious Delta coronavirus variant further gums up supply chains.

“As reopening continues, bottlenecks, hiring difficulties and other constraints could again prove to be greater and more enduring than anticipated, posing upside risks to inflation,” he said in prepared remarks released on Monday.