Article in German and behind a paywall. Here are the relevant excepts, translation by me:

The U.S. government is apparently trying to force Europeans to release large quantities of their strategic diesel reserves onto the market by threatening to halt diesel exports. SPIEGEL learned this from sources within the German government and the European Commission. According to these sources, Washington is demanding that EU member states release 120 million barrels (159 liters each) of diesel from their strategic reserves onto the market, spread out over 180 days. Should this not happen, Washington is threatening to halt its diesel exports to Europe.

The Reuters news agency had previously reported on such a demand by the U.S. government—but had placed it in the context of the release of strategic oil reserves, which had already been agreed upon in March by the member countries of the International Energy Agency (IEA).

However, the U.S. government is now demanding the 120 million barrels of diesel on top, as several insiders in Berlin and Brussels confirmed to SPIEGEL. (…)

120 million barrels of diesel would be an enormous amount, it equates to more than 16 million metric tons. For comparison: Germany’s entire strategic diesel reserve amounts to just over four million metric tons. According to EU figures, all 27 EU member states combined have a reserve of 39 million tons.