And it's not just about Iran, but the whole "Axis of Resistance" Russian alliance. Russia is the biggest supplier of natural gas to Europe, and Iran owns roughly 1/3 of the Persian Gulf gas field, which in collaboration with Russia is trying to export to Europe. Qatar is Iran's economic rival as it owns the rest of the field, and had allied with the US to prevent Russia from winning the EU and China market. I have written a post about this, you might want to check it out.