A statement posted on the Web site of the British Embassy in Abu Dhabi said the country has "a high threat of terrorism."
"We believe terrorists may be planning to carry out attacks in the UAE. Attacks could be indiscriminate and could happen at any time," it said.
Simon Goldsmith, a spokesman for the British Embassy in Dubai, confirmed the heightened alert and said the terror threat level for Britons in the UAE was at the highest level used by the British government.
Goldsmith would not comment on what triggered the heightened alert, but said the threat level was under constant review.
Possible targets include spots popular with expatriates and foreign travelers such as residential compounds, as well as "military, oil, transport and aviation interests," according to the warning posted on the British Embassy's Web site.
