On 2 April 1982, following the 1982 invasion of the Falkland Islands, Britain declared a Maritime Exclusion Zone (MEZ) of 200 nautical miles around the Falkland Islands within which any Argentine warship or naval auxiliary entering the MEZ might be attacked by British nuclear-powered submarines (SSN). On 23 April, the British Government clarified in a message that was passed via the Swiss Embassy in Buenos Aires to the Argentine government that any Argentine ship or aircraft that was considered to pose a threat to British forces would be attacked.