International trade in merchandise by the world’s biggest economies contracted for the first time since 2016 against a backdrop of a stronger dollar and rising protectionism.

Exports by the Group of 20 countries fell a seasonally-adjusted 0.6 percent in the second quarter when expressed in current U.S. dollars, while imports declined 0.9 percent, the Paris-based Organization for Economic Cooperation and Development said on Wednesday. The contraction comes after eight straight quarters of expansion.

While the OECD partly attributed the drop to the depreciation of a number of currencies against the dollar, the data add to concern that protectionism—fueled by the Trump administration’s tariffs—poses the greatest risk to global economic growth.

The biggest drop in exports was recorded in Argentina with 19.9 percent, followed by Brazil and the U.K. Imports contracted most in Turkey.