Iran has started enriching uranium up to 20 percent at an underground facility. That announcement comes as Iran also seized a South Korean-flagged oil tanker in the Strait of Hormuz.
Iran says it seized the tanker because of "oil pollution." Enriching uranium at that level brings Iran one step closer to a weapons-grade level.
It's the latest move escalating tensions after President Trump withdrew from the Iran nuclear deal back in 2018.