Anti-British extremists seeking the return of the Falkland Islands to Argentina have branded her a “pirate princess”, claimed she is hated, and vowed to storm a theatre where she is attending the 125th session of the International Olympic Committee.
It is the first official engagement by a senior royal in Argentina for 14 years.
The IOC added to concerns for her safety by saying they were leaving security to the Argentine Government.
Argentina invaded the Falklands in 1982 only to be defeated after bitter fighting with the Royal Navy-led Task Force.
In recent years, Argentine president Cristina Kirchner has been trying to strangle the Falklands economy.
The Princess Royal is in Buenos Aires for three days as a member of the IOC. But, as she flew in, Argentine extremists threatened to storm the venue – the beautiful Teatro Colon. Protest group Quebracho – which led riots against the British Embassy in Buenos Aires last April – called on Falkland veterans to gather outside the theatre.
Leader Toni Lopez said: “Come pirate Princess Anne of England, daughter of Elizabeth II, the Queen, who ordered the attack on Falklands in 1982. Come if you believe you can walk through Argentina as usual.
“If you come you will have to go into hiding. Because you know that you are hated. Walk through the city and we will be there and we will get into the Colon theatre.”
Quebracho said the arrival of the princess would be met with “dignity and patriotic attitude”.