Gold extended gains after Federal Reserve Chairman Jerome Powell said the U.S. economy faces “significant risks” from slowing global growth, bolstering expectations that the central bank will cut U.S. interest rates further. Copper swung between gains and losses.

Gold extended earlier gains that came after China announced plans to impose additional tariffs in retaliation for President Donald Trump’s latest planned levies. Trump said he would respond to the new China tariffs later Friday.

Trade-policy uncertainty seems to be playing a role in the global slowdown and in weak manufacturing and capital spending in the U.S., Powell said in the text of remarks Friday in Jackson Hole, Wyoming. “We will act as appropriate to sustain the expansion,” he said.

“That’s a very accommodating statement,” Bob Haberkorn, senior market strategist at RJO Futures in Chicago, said by phone. “They’re going to keep this thing going for as long as they can.”

Traders of fed funds futures extended slightly the amount of easing they expect from the U.S. central bank this year after Powell’s remarks. The outlook for lower rates, along with China’s move on tariffs, may help revive investor demand for gold, which erased a weekly loss. Lower rates are a boon for the metal, which doesn’t pay interest.