Drudge is making a big deal with a link to the Reuters story about this.
I doubt they could actually do it. Any attempt to do so would result in the prompt destruction of their limited navy. However, it does accomplish two things:
It sends the price of oil higher with escalated tensions in the region. Also, it exposes our dependence on foreign suppliers (even if the major contributors are neighbors). We need an energy policy to take this potential weapon away from those who may wield it.