Finance officials from the Group of 20 economies say that disruptions to global supply chains pose a potential risk to growth.
They voiced their concern a week after China announced a tightening of restrictions on rare earth exports.
South Africa chaired the meeting of G20 finance ministers and central bank chiefs in Washington and issued a summary after it wrapped up on Thursday.
The statement did not mention China by name, but said global economic growth faces ''complex'' challenges including trade tensions and supply chain disruptions.
Japan's finance minister Kato Katsunobu was among Group of Seven finance chiefs who raised concerns about China's rare earth restrictions when they met earlier.
Beijing announced last week that it will ban rare earth exports for military use and limit exports of related technologies.
The move came amid trade tensions sparked by the Trump administration's introduction of tariff measures.
Washington has expressed readiness to impose an additional tariff on imports from China. That has raised concern that trade friction between the world's two largest economies will escalate and increase uncertainty about the global economic outlook.
The G20 summary said members had agreed that economic imbalances should be ''addressed through country-specific reforms and multilateral coordination.''

Quiz 1:
Which countries are part of the Group of 20 economies?
A. Group of 18 economies
B. Group of 20 economies
C. Group of 30 economies
D. Group of 5 economies

Quiz 2:
Who chaired the meeting of G20 finance ministers and central bank chiefs in Washington?
A. United States
B. China
C. Japan
D. South Africa

Quiz 3:
What is one of the challenges that global economic growth faces according to the G20 statement?
A. Currency fluctuations
B. Political instability
C. Trade tensions and supply chain disruptions
D. Natural disasters