Argentina has declared that it is taking control over all shipping between its coast and the Falklands, in effect awarding itself the power to blockade the disputed islands.

According to a decree issued by President Kirchner last night, all ships sailing through the waters claimed by Argentina must hold a permit. The measure seems likely to deepen a row over conflicting claims to oil beds lying inside the Falkland Islands’ territorial waters.
Argentina to blockade Falkland waters in dispute over oil rights - Times Online