The UN has called Yemen the "largest humanitarian crisis in the world".
On Friday, UN spokesman Stephane Dujarric called on the rival sides to allow humanitarian aid access, including through Sanaa airport which has been closed to all but limited UN flights for a year.
United Nations spokesman Stephane Dujarric said he was "unaware" if there was any formal request from Saudi-led coalition, despite regular contacts between the worldwide body, coalition and Yemeni government.
The Yemeni navy has warned the Saudi-led military coalition, which is assisting Riyadh in its war on Yemen, against any adventurism in the Red Sea, efforts to prevent humanitarian convoys from reaching the strategic port city of Hudaydah and attacks on Yemeni fishermen.
The Saudi-led coalition fighting rebels in Yemen asked the United Nations to help re-open Sana'a airport on Thursday, a day after an aid group said Yemenis were dying because they could not seek medical help overseas.
The four men killed when their helicopter crashed in Yemen on Friday. Courtesy Aletihad
Yemen has been locked in a power struggle between Saudi-backed President Abd Rabu Mansour Hadi and the Iran-allied Houthi rebels since 2014.
Those people also face a deadly cholera outbreak and looming starvation.
"The General Command of the UAE Armed Forces on Friday mourned the death of the four martyrs, who fell while carrying out their routine duties in Shabwah, Yemen, as their helicopter crash-landed after sustaining a technical failure", WAMreported.
The pilot made an emergency landing in a government-held area, "resulting in minor injuries to the crew".
UAE-trained Yemeni special forces backed by the United States earlier this month launched a major operation against Al-Qaeda, driving it from the oil-rich Shabwa province.
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