The handover was supposed to be the first in a series of confidence-building measures agreed to in Sweden that could pave the way for a political settlement of Yemen's 4-year-old war pitting the rebels known as Houthis against the internationally recognized government backed since 2015 by a Saudi-led coalition.
Across the Middle East, countries locked out of purchasing U.S.-made drones due to rules over excessive civilian casualties are being wooed by Chinese arms dealers, who are world's main distributor of armed drones.
The U.S. has rejected three separate requests from the United Arab Emirates for military assistance in the Saudi-led coalition attack on the Yemeni port of Hodeida, a senior UAE official said Thursday.