Explaining the US blockade of Iranian ports in 2 minutes

The United States began blockading Iranian ports after peace talks between the two countries ended without an agreement last weekend.

U.S. President Donald Trump warned in a social media post that any Iranian “fast attack vessel” caught trying to approach the blockade area would be “immediately eliminated.”

But what will the blockade do and what are its risks? BBC security correspondent Frank Gardner explains how this works and the potential impact on the world.