Aden: In Taez, Yemen’s third biggest city, forces loyal to exiled president Abd Rabbo Mansour Hadi were searching for 1,200 inmates, including Al Qaida members, who made a mass breakout as the prison was captured from Al Houthi forces.

A loyalist source accused the militiamen of deliberately throwing open the gates in an apparent attempt to cover their withdrawal.

“Between five and eight Al Qaida members were among the prisoners,” a military source said.

There have been repeated jailbreaks in Yemen since Al Houthi militiamen launched an offensive last summer, overrunning the capital and then much of the rest of the country.

Al Qaida’s Yemen arm took advantage of the rebellion to seize the southeastern port city of Mukalla in April where it freed more than 300 inmates, including one of its leaders.

Al Houthi fire on a residential district of Yemen’s second city Aden killed at least 20 civilians on Wednesday as loyalist forces in central city Taez launched a manhunt for 1,200 escaped prisoners.

Both cities have seen heavy fighting as Hadi loyalists battle to fight back Al Houthi militiamen with the support of a Saudi-led bombing campaign launched in March.

Aden was Hadi’s last refuge before he fled into exile in neighbouring Saudi Arabia in March and his loyalists have been battling to defend it against the militiamen and renegade troops.

Al Houthis and their allies pounded the loyalist-held Al-Mansura district with 15 Katyusha rockets, loyalist forces spokesman Ali Al Ahmadi said.

The rocket fire began before dawn when the streets were busy ahead of the daytime fast observed by Muslims during Ramadan, Ahmadi said.

A fresh salvo of rockets later in the morning hit mourners burying some of the dead from the earlier fire, the spokesman and witnesses said.

Medics said 41 people were also wounded, many of them seriously.

During the night, militia positions in the nearby neighbourhoods of Dar Saad and Khor Maksar had been hit by a series of Saudi-led air strikes, residents said.

A coalition strike in neighbouring Lahj province killed 13 militiamen, a local official said.

On Monday, UN chief Ban Ki-moon called for an investigation after air strikes hit the UN Development Programme compound in Aden, wounding a guard and causing serious damage.

On Tuesday Human Rights Watch said that strikes on the militia stronghold of Saada in Yemen’s northern mountains had destroyed houses, markets and a school, in what could amount to war crimes.

An attack claimed by Daesh on Al Houthi leaders in the rebel-held capital Sana’a killed at least 28 people on Monday, medics said.

The United Nations has called repeatedly for a humanitarian ceasefire to allow the delivery of desperately needed relief supplies.

UN envoy Esmail Ould Shaikh Ahmad renewed the appeal in talks with Hadi in the Saudi capital late on Tuesday, a government source said.

“The government is coming under pressure from the United Nations for a truce,” the official said.