Ukraine may be behind a string of drone and ground attacks against Sudanese paramilitaries, which are backed by the Russian Wagner mercenary group.
A Ukrainian military source told CNN that the operation was the work of "a non-Sudanese military," and said Ukrainian special services were likely responsible for the attacks targeting the Rapid Support Forces (RSF).
The RSF has been locked in a bloody war with the Sudanese armed forces since mid-April with fighting focused mostly around the capital Khartoum.
CNN has asked experts to verify at least 14 videos, widely shared on social media, that seemingly show drone strikes.
"One of the video clips also showed words in English and the Ukrainian language on the control unit of one of the drones, while the same clip showed the person responsible for controlling the drone," the network said.
The date of these videos is unclear, while a Kyiv official did not deny or confirm Ukrainian involvement in the drone programme.
The Russian Wagner group – whose leader was killed in a helicopter crash last month - is believed to be backing the RSF.
In April, US officials revealed that Wagner offered powerful weapons, such as surface-to-air missiles, to RSF chief Mohammed Hamdan 'Hemedti' Dagalo.
Moscow carried out a full-scale invasion of Ukraine in February last year and has illegally annexed large parts of east Ukraine, with help of Wagner mercenaries.
A Ukrainian counteroffensive has seen Kyiv regain some territories and carry out drone strikes deep in Russia.