In Tehran, celebrations of the Moslem New Year – Norouz – will start on Sunday and last 5 days.
Afghanistan’s and Iraq’s presidents have already come to the festivities.
The presidents of Armenia, Tajikistan, Turkmenistan, the crown prince of Qatar and the vice premier of Kirgizia are also expected. In total, delegations from 25 countries will take part.
The Moslem New Year is on March 21.
Last year, the UN’s General Assembly made this day an international holiday.