According to the International Maritime Organization, some 20,000 civilian seafarers are stuck on board trapped ships and the other utility and support vessels.
The regulations allow the government to target foreign organizations and individuals if they suspend normal trade with China in violation of market rules.
The charges deliver on threats the president made last fall to impose 100% tariffs on branded or patented medicines unless companies move production to the U.S.
The three ships transiting are particularly interesting because they are the largest type of oil tankers and the first LNG carrier to escape the gulf since the war began.