A purported affiliate of the Islamic State group has claimed responsibility for the mass killing of 29 soldiers last week in a southern city taken over the country's local al-Qaida branch.

They made the claim Monday on a Twitter account known to be associated with the militants, who previously claimed responsibility for suicide bombings Friday in Yemen's capital, Sanaa, that killed 137 people. U.S. officials have been skeptical about whether the militants have direct links to the Islamic State group.

Al-Qaida in Arabian Peninsula took over the city of al-Houta on Friday before being pushed out by Yemeni forces. Al-Qaida militants had not claimed the soldiers' killing in al-Houta.

The chaos comes as the country's embattled president faces a Shiite rebel insurrection.