DUBAI, United Arab Emirates (AP) — President Donald Trump said Thursday he has ordered the U.S. military to “shoot and kill” small Iranian boats that deploy mines to choke traffic through the Strait of Hormuz.

Trump’s post on social media came shortly after the U.S. military seized another tanker associated with the smuggling of Iranian oil, ratcheting up a standoff with Tehran over the strait through which 20% of all crude oil and natural gas traded passes.

The Associated Press