Two Emirati pilots were killed when their fighter jet crashed during a mission against Houthi rebels in Yemen, the Saudi-led coalition has said.
A coalition statement said the plane had suffered a technical failure.
The UAE is part of the coalition which has been carrying out air strikes since March 2015 in support of ousted President Abedrabbo Mansour Hadi.
It is the first known loss of an Emirati jet in the conflict in which some 6,000 people have been killed.
About half of the deaths have been civilian, the UN says.
The plane crashed in a mountainous area near the southern city of Aden, local officials and witnesses said.
The UAE Air Force operates both F-16 and Mirage 2000 fighter jets.
In December, a Bahraini F-16 crashed in Saudi Arabia due to a "technical error", while in May a Moroccan warplane came down over Yemen.
Both jets were taking part in the Saudi-led campaign in Yemen, codenamed Operation Restoring Hope.
The UN has criticised both the coalition campaign and the Houthis over the scale of civilian casualties.