"We need sustainable sources of revenue that do not rely on further taxing workers' wages and exacerbating the economic disparities that we are all committed to reducing," Yellen said.
"We need to put an end to corporations shifting capital income to low tax jurisdictions, and to accounting gimmicks that allow them to avoid paying their fair share."
"The Delta variant is more transmissible than other circulating variants and we estimate that by the end of August it will represent 90 percent" of new cases in the EU, she added.