UAE President Sheikh Khalifa bin Zayed Al Nahyan died at the age of 73, Emirates news agency WAM reported on Friday.
The Ministry of Presidential Affairs declared official national mourning for the death of the president for 40 days from Friday. Flags will fly at half-mast during this period.
Work in both public and private sectors will be suspended for three days, also from Friday, a Dubai Media Office report clarified.
Under the constitution, vice-president and premier Sheikh Mohammed bin Rashid Al Maktoum, ruler of Dubai, will act as president until the federal council which groups the rulers of the seven emirates meets within 30 days to elect a new president, Reuters reported.