Oil prices plunged 7% on Friday, settling at their lowest close in more than three years, as China ramped up tariffs on U.S. goods, sharply escalating a global trade war that has investors worried about a recession.

Fears that China's tariff retaliation against the U.S increases the probability of a global recession is hitting commodity prices hard. U.S. West Texas Intermediate oil futures are down nearly 8% to $61.