The Islamic State of Iraq and the Levant (ISIL) group's Yemen affiliate has claimed responsibility for an attack on an Arab coalition base that killed at least 15 troops, including four Emirati soldiers.
ISIL join the fray in Yemen's complex war
The armed group made the claim through its affiliated accounts on Twitter on Tuesday, posting a series of photos depicting the bombings and pictures of the suicide attackers involved.
"Four martyrdom operations targeted a gathering of Saudi, Emirati, and Yemeni offices," a statement released by the group said.
The names of the attackers in the pictures suggested those involved were all Yemeni in origin.
Al Jazeera's Hashem Ahelbarra said the claim of responsibility by ISIL marked the start of "strange scenario" in Yemen.
"On one hand we have government forces and the Saudi-led coalition fighting the Houthis, and now you have ISIL fighting the government and Houthi forces," Ahelbarra said.
"You'll have the (southern) secessionists fighting al-Qaeda, and ISIL fighting al-Qaeda at the same time...It will be a complete nightmare scenario in the near future."
"In 2014 ISIL emerged saying that they were there to defend Sunnis who had been undermined by the Shia...they were present in the capital Sanaa but now they're trying to build a platform in the south."
The explosions hit a hotel housing Yemeni officials and a Gulf military base in Aden, a government spokesman and residents said, in the biggest attack on the government since it retook the city from its Houthi foes in July.
Official news agency said of the dead, four were Emiratis and one was Saudi.
Members of the Gulf coalition have been providing security at the luxury al-Qasr hotel, and Yemeni government officials' presence there makes it a highly symbolic target for the rebels.
Witnesses said the hotel was on fire and that there are ambulances at the scene.
ISIL has previously attacked mosques belonging associated with Zaydi Muslims, the branch of Shia Islam the Houthis adhere to, but supporters have also carried out attacks in Saudi Arabia and Kuwait.
In August, at least 15 people including Saudi soldiers were killed when ISIL operatives attacked a mosque used by Saudi special forces, in a region bordering Yemen.
Yemen has been embroiled in fighting that pits the Shia rebels known as Houthis and forces loyal to a former president against the Saudi-backed and internationally recognised government.
The Saudi-led coalition has been carrying out airstrikes against the rebels and their allies since March.
The Emirates and other members of the coalition see Yemen's second-largest city of Aden as a key foothold in restoring Yemen's government to power as they and their Yemeni allies attempt to push the rebels from the capital, Sanaa.