Yemen was previously the preserve of IS’s jihadist rival Al-Qaeda, which controls swathes of the south and east, but since March the group has claimed a string of high-profile attacks.
Eight women were among the dead.
The jihadist group considers Shiites heretics and has repeatedly targeted them not only in Yemen but in countries across the region.
On June 17, the IS claimed to have launched four auto bombing attacks against three mosques and a Houthi office in Sanaa, in which 18 people were killed and dozens wounded.
Saudi Arabia and its Gulf allies are demanding that the Huthis pull back from territory seized in their offensive and that President Abedrabbo Mansour Hadi be restored to power.
The captives, including convicted murderers, were being held outside Taez in southwestern Yemen, when the jail was overrun by fighters of the pro-government’s Popular Resistance Committees.
“This is another message to the forces of oppression,” he added, promising “new surprises in the coming days”.
Another loyalist source said their forces were now trying to round up the escapees.
Saudi Arabia had earlier this month reported that it had shot down a Scud missile fired into the kingdom by Houthis, in the first use of the missile in over two months of war.
But it said that a Saudi soldier had been killed on Monday by rebel fire across the border.
San’a Province made headlines in March, when it claimed twin suicide bombings at Shiite mosques in San’a that killed more than 130 people.
SANAA Around 1,200 prisoners, including al Qaeda suspects, escaped during clashes at a jail in central Yemen on Tuesday, officials said.
It called on Saudi Arabia and its coalition partners to observe the laws of war, promptly investigate all alleged violations, and provide appropriate compensation to civilian victims.
Thomson ReutersA boy walks as he collects toys from the rubble of a house destroyed by a recent air strike in Yemen’s northwestern city of SaadaDUBAI (Reuters) – Air strikes by a Saudi-led Arab coalition on the northern Yemeni city of Saada, a Houthi rebel stronghold, have killed dozens of civilians and wrecked homes and markets, Human Rights Watch said on Tuesday.
A local official accused the rebels of firing on a Qatari aid ship preventing it from docking in the city, which is in desperate need of relief supplies.