Yemeni separatists have taken control of the strategic city of Aden after days of fighting with forces backing the internationally recognized government.

A spokesperson for the Southern Transitional Council (STC) told CNN the group took over the city including its presidential palace, port and airport. Aden has been the seat of the Saudi-backed government since Houthi fighters took over Sanaa in 2014.

"We are not inside the presidential compound, which is on an island, but we have secured its entrances and exits," Nizar Haytham, the STC spokesperson, told CNN.

CNN wasn't able to verify the claims. However, the interior minister of the country's internationally recognized government conceded a defeat in what he called a "successful coup."

"The successful coup destroyed what's left of this country's sovereignty," Ahmed Al-Maysary said in a video circulated on social media.

He said he recorded the video in Aden right before fleeing to Riyadh. He was the only minister on the ground making statements to the public about the fighting.

The Aden International Airport was closed and flights have been diverted to Sayoun airport since Friday, according to Yemen Airways flight schedule.

Some 40 people have been killed and 260 injured in the fighting in Aden, according to preliminary reports cited by the UN Office for the Coordination of Humanitarian Affairs (OCHA).

"It is heart-breaking that during Eid al-Adha, families are mourning the death of their loved ones instead of celebrating together in peace and harmony" said Lise Grande, UN humanitarian coordinator in Yemen.

In a bid to defend the city, the Saudi-led coalition said earlier it hit a target posing "direct threat" to the embattled government and ordered the STC to withdraw immediately.

The coalition didn't specify the target, but warned that "this is the first operation and it will be followed by another, in case no one abides by the coalition' statements," Saudi state TV reported.

However, Haytham downplayed the attack, telling CNN the coalition airstrike hit an empty field in the presidential compound in Aden.

The fighting between the southern separatists and the government in Aden illustrates the complexity of the conflict in Yemen.

Both sides are part of the coalition fighting the Iran-backed Houthis in the north, but each is backed by a different member state of that coalition.

The southern separatists are supported by the United Arab Emirates, while the United Nations-recognized government of Abdu Rabbu Mansour al-Hadi has been propped up by Saudi Arabia.

The two sides had previously clashed over control of Aden.

In the statement on Sunday, Al-Maysary accused the STC of using UAE vehicles and weapons in its takeover of the coastal city and "congratulated" UAE on the "victory."

Saudi King Salman Bin Abdelaziz met with the exiled Yemeni president in Riyadh on Sunday, according to the Saudi official news agency. Saudi Arabia has played a major role in the conflict, leading the coalition against the Houthis.

Separately, the STC said it has accepted an invitation for talks with the internationally-recognized government that would take place in Riyadh. A date has not been set yet, it said.

-Reuters