The younger sister of Queen Maxima of the Netherlands has died at the age of 33, a palace spokeswoman said in The Hague on Thursday.
"We have to announce that the queen's sister died on Wednesday night in Buenos Aires," the spokeswoman said. 
Queen Maxima and her sister, Ines Zorreguieta, were both born into an Argentinian family. 
The queen has cancelled all her scheduled appearances until the end of next week, including visits to Latvia, Estonia and Lithuania, a palace statement said. King Willem-Alexander will now make the appearances alone.
In a message of condolence, Dutch Prime Minister Mark Rutte described the news as "a big shock."
Broadcaster NOS reported that Zorreguieta had been receiving treatment for psychiatric problems.
The palace spokeswoman said the death was a "suspected suicide."