United Arab Emirates President Sheikh Khalifa Bin Zayed Al Nahyan has died, state news agency WAM reported on Friday.
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.
Khalifa, who was born in 1948, came to power in 2004 in the richest emirate Abu Dhabi and became the head of state.
He is expected to be succeeded as ruler of Abu Dhabi by his half-brother Crown Prince Sheikh Mohammed bin Zayed al-Nahyan.
Mohammed bin Zayed has been the de facto ruler of the U.S.-allied UAE, particularly after Khalifa suffered a stroke in 2014, following which he has rarely been seen in public.