‘The Supreme Command of the Armed Forces announced today that a fighter jet taking part in the Arab coalition led by Saudi Arabia... in Yemen was missing,’ said a statement on the official WAM news agency.
It is the first known case of an Emirati jet from the coalition going missing since the Saudi-led campaign began in March last year.
Coalition warplanes turned their crosshairs on Yemen's second city Aden for the first time last week.
Security officials and witnesses told AFP that a jet had crashed into a nearby mountain on Monday as coalition warplanes operated in the vicinity after clashes erupted between Yemeni forces and jihadists.
Al-Qaeda and the Islamic State group have taken advantage of the conflict between Iran-backed insurgents and pro-government forces to reinforce their presence in the south, including in Aden.
Apache helicopters were taking part in the fighting on Monday, security officials said.
‘We saw Apache helicopters fire rockets and open machine gunfire at Al-Qaeda militants’ in Aden's Mansura district, one witness said.
Security sources estimate that around 300 heavily armed Al-Qaeda fighters are entrenched in Mansura.
The UAE did not immediately give details on the missing plane.
In December, a Bahraini F-16 crashed in Saudi Arabia due to a ‘technical error.’
The pilot was saved and the plane's wreckage was found.
It was the second coalition jet to crash after a Moroccan warplane went down during a mission over Yemen in May.
Its pilot was later found dead and his body was returned home.
The coalition said at the time that crash had been caused by a technical fault or human error, and it denied rebel claims that they downed the plane.
Saudi Arabia and the UAE, which play key roles in the coalition, have suffered the alliance's heaviest losses in Yemen, with dozens of soldiers killed.
In Yemen itself, more than 6,100 people have died -- half of them civilians -- since the coalition launched its campaign in March 2015, according to the United Nations.
