DUBAI (Reuters) - The United Arab Emirates (UAE) President Sheikh Khalifa bin Zayed al-Nahyan has returned home after a private trip abroad, state news agency WAM said, in a rare report on the U.S.-allied leader's movements since he suffered a stroke in 2014.

It did not give any details about where he traveled.

The pro-Western modernizer and head of the ruling family of Abu Dhabi, the largest of the federation's seven emirates, has been president since the death of his father, Sheikh Zayed bin Sultan al-Nahyan, in 2004.

For much of the past decade, Sheikh Khalifa's younger brother Sheikh Mohammed bin Zayed al-Nahyan, the Crown Prince of Abu Dhabi, has led negotiations on behalf of the UAE, a major oil producer, in sectors ranging from energy and defense to investment and politics.

(Reporting by Dubai newsroom; Editing by Nick Macfie)