The Trump administration has intensified sanctions against foreign companies linked to Iran, escalating tensions in the Strait of Hormuz as it prepares for a summit with Chinese President Xi Jinping. The U.S. Treasury Department sanctioned Chinese and Hong Kong companies for allegedly supporting Iran's drone production, and also added Chinese refineries linked to Iran's oil exports. The U.S. military has strengthened maritime security by striking oil tankers in the Strait of Hormuz.