WASHINGTON—U.S. Treasury Secretary Janet Yellen on Tuesday told European Commission Executive Vice President Valdis Dombrovskis that cooperation was needed on “further strong measures” in response to Russia’s invasion of Ukraine after unprecedented sanctions, the U.S. Treasury said. “Secretary Yellen affirmed the United States’ support for Ukraine’s sovereignty, working together with our partners to hold Russia accountable,” the Treasury said in a statement after a call between the U.S. and EU officials. By David Lawder