From the German capture of Denmark and Norway, the Swedish overseas trade during World War II was mainly blocked by the battle of the Atlantic, but Swedish diplomats convinced Germany and the United Kingdom to let through a few vessels, mainly to the United States until their entrance into the war, and neutral countries in Latin America. These transports, called lejdtrafiken, "the safe conduct traffic", were monitored by both powers, and ten of them were sunk during the war. Sweden mainly imported petroleum products and agricultural produce, and exported wood products. Overall, petrol imports to Sweden greatly decreased, and substitute fuels were found.