At least 26 people were killed Wednesday as explosions rocked Yemen’s Aden airport moments after a new unity government flew in, in what some officials charged was a “cowardly” attack by Iran-backed Houthi rebels.

Although all government ministers were reported to be unharmed, more than 50 people were wounded, medical and government sources told AFP in the southern city, with the casualty toll feared likely to rise.

Doctors Without Borders said it was preparing a “mass casualty medical response plan”.

The International Committee of the Red Cross said one of its employees was among those confirmed dead and “two others are unaccounted for and three were injured”.

As smoke billowed out of the airport terminal from an initial blast, with debris strewn across the area and people rushing to tend to the wounded, a second explosion took place.

Video footage shot by AFP appears to show missile-like ordnance striking the airport apron, that moments before had been packed with crowds, and exploding into a ball of intense flames.

It was not immediately clear what had caused the explosions.

On Wednesday evening, an explosion was heard near the presidential palace in Aden.

The Saudi-led coalition said: “A Houthi drone which attempted to target Al-Masheeq Palace was shot down.”

Yemen’s internationally recognised government and southern separatists formed a power-sharing cabinet on December 18, forging a joint front against the Houthi rebels who have seized Sanaa and much of the country’s north.

Information Minister Moammar al-Eryani said all members of the new government had escaped unharmed from the blast, which he blamed on the Houthi rebels.

“We assure you that the cowardly terrorist attack by the Iran-supported Houthi militia will not deter us from carrying out our patriotic duty,” Eryani tweeted.

Foreign Minister Ahmed bin Mubarak too blamed the rebels but President Abedrabbo Mansour Hadi held back.

“The terrorist acts perpetrated by the Iranian-backed Houthi militia and extremist terrorist groups will not discourage the legitimate government from exercising their duties,” Hadi said without specifying which he held responsible for the airport attack.

Government spokesman Rajih Badi called for an international investigation.

“It is too soon to accuse any party before an investigation reveals who executed the attack, including (accusing) the Houthis,” he told AFP, adding that the casualties included civilians, security guards and local officials.

UN envoy Martin Griffiths condemned the attack, calling it an “unacceptable act of violence”.

“I wish the cabinet strength in facing the difficult tasks ahead. This unacceptable act of violence is a tragic reminder of the importance of bringing Yemen urgently back on the path towards peace,” he said.

The cabinet members arrived in Aden days after being sworn in by Hadi in Saudi Arabia, which leads a military coalition against the insurgents.

Hadi fled to Riyadh after Sanaa fell to the Houthis in 2014.

Tens of thousands, mostly civilians, have been killed and millions displaced in Yemen’s grinding five-year war, which has triggered what the United Nations has called the world’s worst humanitarian disaster.

The new government includes ministers loyal to Hadi and supporters of the secessionist Southern Transitional Council, as well as other parties.

While all oppose the Houthi rebels, deep divisions have grown among them.

Saudi Arabia has been encouraging the unity government to quell the “war within a civil war” and to bolster the coalition against the Houthis, who are poised to seize the key town of Marib, the last government stronghold in the north.

Saudi ambassador Mohammed Al Jaber, said that “targeting the Yemeni government upon its arrival at Aden airport is a cowardly terrorist act targeting all the Yemeni people, their security, stability and their daily life.”

The United Arab Emirates, which has backed the southern secessionists, said the Aden airport attack was “nothing but a sinister project that seeks to undermine the chances of security and stability”.