Speaking in a conference Brussels, U.S. Defense Secretary Lloyd Austin on Thursday praised Ukrainian “resilience” as senior Pentagon officials said they expect a lengthy and “very violent” fight during Ukraine’s counteroffensive to drive out Russian troops.

Austin said military equipment and training would continue to flow, ensuring that Kyiv can “prevail over [Russian President Vladimir] Putin’s campaign of cruelty and conquest.” He also met with his Ukrainian counterpart at a meeting of the Ukraine Defense Contact Group, which includes ministers from almost 50 countries assisting Kyiv’s war efforts. “Ukraine’s fight is a marathon and not a sprint,” Austin noted in his opening remarks.