Washington, Feb. 26 -- A slump in U.S. refining activity and disruptions to global trade have tightened diesel supplies in recent weeks, dampening historically high U.S. diesel exports to Europe this month.

Difficulties in securing U.S. diesel complicate an existing supply crunch in Europe, which previously relied on Russian fuel exports. U.S. diesel cracks briefly surged to a four month high of over $48 a barrel this month, crimping arbitrage opportunities to ship the fuel to Europe. Many of Europe's other suppliers in the Middle East and Asia have been forced to traverse around the Cape of Good Hope due to Houthi attacks on vessels in the Red Sea, adding lengthy delays and making that trade less profitable too. European imports of U.S....