Argentina has imposed new controls on shipping to the Falkland Islands in a growing oil dispute with the UK.
The Argentine government has ordered ships heading to the islands via its waters to apply for permission first.
The move comes as Argentina has become increasingly agitated at the forthcoming start of oil drilling in Falkland Islands territorial waters.
Argentina claims sovereignty over the British Overseas Territory, and it invaded the islands in 1982.
The UK sent a taskforce which seized back control over the Falklands after a short war in which 649 Argentine and 255 British soldiers died.
Although that conflict was 28 years ago, tensions remain over the islands - which Argentina calls the Islas Malvinas.
Earlier this month, Argentina protested to the UK about the start of the oil drilling work, which is expected to begin in the first half of this year.
Argentine President Cristina Fernandez on Tuesday signed a decree that requires all vessels travelling between Argentina and the islands or those that want to cross Argentine territorial waters en route to the Falklands to seek prior permission.
The government Cabinet Chief Anibal Fernandez said the decree sought to achieve "not only a defence of Argentine sovereignty but also of all the resources" in the area.
He said the measure also applied to vessels going to the other nearby British controlled islands in the South Atlantic - South Georgia and the South Sandwich Islands.
The British Foreign Office said the decree would not affect shipping through the area.
"Regulations governing Argentine territorial waters are a matter for the Argentine authorities. This does not affect Falkland Islands territorial waters which are controlled by the island authorities," its said in a statement.
It added that Argentina and Britain were "important partners" and pledged to "co-operate" on issues in the South Atlantic, where the Falklands are located.
A drilling rig from the Scottish highlands, the Ocean Guardian, is expected to arrive in the coming weeks to begin oil exploration.
Geologists think the South Atlantic ocean bed surrounding the Falklands could contain rich energy reserves.
If Argentina's government is unpopular, they might try an invasion stunt like in the 80's to boost their popularity, though that seems unlikely now. Be interesting to see how this pans out, what are peoples views on the sovereignty of the islands?