Saudi-backed militants and UAE-led separatists have clashed in the Yemeni port city of Aden amid Riyadh war against the impoverished Yemeni nation.

Eyewitnesses said the infighting broke out between the southern UAE-backed separatists and Saudi-backed militants loyal to ex-Yemeni president Abd Rabbuh Mansur Hadi.

It came after the Storm Brigades affiliated with the Southern Transitional Council which is backed by the UAE made an attempt to break into Camp 20 which is supported by Saudi Arabia.

On Friday, Saudi forces attempted to take control of Aden International Airport from the so-called Emirati-trained Security Belt Forces in order to hand it over to other local forces receiving military training in the kingdom. 

Both the UAE-sponsored separatists and the Saudi-backed militants loyal to Hadi serve the Riyadh-led military coalition and have been engaged, since March 2015, in a bloody war on Yemeni people.

Ties between the two sides have soured over a number of issues, including what the Yemenis view as the UAE's intention to occupy Yemen’s strategic Socotra Island and gain dominance over
major waterways in the region.

The US-based Armed Conflict Location and Event Data Project (ACLED), a nonprofit conflict-research organization, estimates that the Saudi war on Yemen has claimed more than 100,000 lives over the past nearly five years.

Saudi Arabia and the United Arab Emirates have purchased billions of dollars worth of weapons from the United States, France and the United Kingdom in their war on Yemen.

The UN says over 24 million Yemenis are in dire need of humanitarian aid, including 10 million suffering from extreme levels of hunger.