Bombers driving military vehicles

The suicide bombers in Aden were driving Yemeni army vehicles, a Yemeni military source told Reuters. UAE officials earlier in the day had blamed the Houthis and their ally, former president Ali Abdullah Saleh, for the attacks.

Houthi official Yahya Ali al-Qahoom distanced his group from the bombings. The Shi'ite Houthis have long accused Saudi Arabia and the Yemeni government of being allied to Sunni Muslim militants like Islamic State, something both deny.

"The blows which the invaders have received in Aden signal the depth of the struggle going on among factions and the intelligence agencies of the aggressor countries," Qahoom said on his Twitter account, referring to the Saudi-led coalition.

Islamic State distributed pictures on Twitter showing smiling men it said were the suicide bombers and the hotel at the moment it was hit by a big orange fireball.

Salem al-Yazidi, a fighter in a local militia allied with President Abd-Rabbu Mansour Hadi, who remains in sanctuary in Saudi Arabia, described chaotic scenes when he rushed to aid the victims of the blast at the plush al-Qasr hotel.

"There was a big hole in the ground and what looked like the limbs of the bomber around it," Yazidi told Reuters.

The Houthis are locked in ground fighting with Yemeni and Gulf Arab forces and also in the cross-hairs of daily Saudi-led air strikes. In the biggest blow yet to the coalition, the Houthis killed over 60 Gulf Arab troops in a rocket attack in Marib, east of Sanaa, last month.

The plush al-Qasr hotel is serving as informal headquarters of Yemen's government and of Emirati troops based in Aden.

Rajeh Badi, spokesman for the Yemeni government, said it would remain in Aden to carry on its duties for the time being.

Hadi's government has demanded the Houthis recognise its authority and withdraw from several cities, including Sanaa, which they seized last year. United Nations efforts to settle the conflict have made little progress.

In a separate attack in eastern Yemen, a local official said forces loyal to Hadi foiled an attempt by al Qaeda militants on Tuesday to seize facilities at the al-Masilah oilfield in Hadramout province. The official said there were casualties on both sides in the gunfight but provided no further details.