North Korea observes three days of national mourning for Fidel Castro

North Korea's is taking part in three days of mourning for former Cuban leader Fidel Castro at the behest of leader Kim Jong Un, ending on Wednesday.

All flags outside official buildings will be flown at half-mast in honour of the iconic revolutionary leader during the mourning period, but it is unclear how else Castro's passing has been marked.

Kim Jong Un sent a wreath to the Cuban embassy as a mark of respect, and a delegation of senior North Korean officials set off for Havana to attend Castro's memorial service.

In a statement released after Castro's death, Kim Jong Un said that Castro was a "close friend and comrade" of the Korean people.

Castro "made all efforts to strengthen the friendly and cooperative relations between the two parties, governments and peoples of our two countries and extended firm support and encouragement to our efforts for national reunification and just cause with the invariable revolutionary principle and obligation for over half a century," according to the statement.

Fidel Castro is the first foreign political figure to be honoured in such a way since Palestinian leader Yasser Arafat passed away in 2004.