The Twitter account of Spain's royal family has published photos of King Juan Carlos I offering his letter of abdication to the country's Prime Minister, Mariano Rajoy.
Juan Carlos, who has been on the throne almost 40 years, will be replaced by his son, Crown Prince Felipe.
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The talks descended into crisis on Friday when Canada's trade minister Chrystia Freeland walked out of meetings.
Police in New York are still investigating what the substance is and whether it could be harmful.
The Sherlock actor made the comment while he received an award for his humanitarian work.