WASHINGTON (AFP) ― Federal Reserve chief Janet Yellen warned Friday that the gap between the rich and poor in the United States is widening and is near the highest levels seen in 100 years.

In a speech at a conference on inequality in Boston, Yellen did not mention monetary policy nor the current turmoil in financial markets.

Instead, she focused on the widening wealth disparity and how that impacts economic opportunity.

“By some estimates, income and wealth inequality are near their highest levels in the past hundred years,” Yellen said, noting the gap has grown steadily over recent decades, despite a brief pause during the 2008 crisis.

During the recession, the worst since the Great Depression of the 1930s, the richest Americans lost money, and increased government spending helped offset losses for the less wealthy.

“But widening inequality resumed in the recovery, as the stock market rebounded,” Yellen said, noting that “wage growth and the healing of the labor market have been slow, and the increase in home prices has not fully restored the housing wealth lost by the large majority of households for which it is their primary asset.”

The Fed chief said that wide wealth disparities can make it harder for the poor to move up the income ladder, and also warned of the burden of student loan debt, which quadrupled between 2004 and 2014.

“I think it is appropriate to ask whether this trend is compatible with values rooted in our nation’s history, among them the high value Americans have traditionally placed on equality of opportunity,” she said.

The 68-year-old Yellen, who has headed the Federal Reserve since early this year, is known as a “dove,” referring to her policies that prioritize fighting unemployment in contrast to “hawks” who prioritize keeping inflation low.

In one of her first major speeches as chair, Yellen spoke on what the Fed was doing “to promote a stronger job market,” where she said that, “although we work through financial markets, our goal is to help Main Street, not Wall Street.”