Two apparently synchronized bombs have exploded in the southern city of Aden, killing two people and wounding 12 others.
The first bomb went off outside a sports club in the port city, wounding four people and sending police and rescue units rushing to the scene.
The second bomb exploded once they had arrived, injuring 10 more, including three soldiers. A security official told the Associated Press that the two people killed were civilians who died of their wounds at a hospital.
Qassim al-Rimi, the leader of Al-Qaeda in the Arabian Peninsula (AQAP), the organisation's Yemen offshoot, announced on Monday via an Internet recording the formation of an "Aden-Abyan Army" that would free the country of "crusaders and their apostate agents," according to the AFP news agency.
The recording was posted on the Al-Malaham website.
"We are preparing to implement the first steps of the Aden-Abyan Army to defend the nation and its religion," al-Rimi said. "This army is in its early stages".
Al-Rimi also said that the "army" was avoiding direct confrontation with Yemeni authorities in urban areas and was conducting a "war of attrition". Aden has a population of around 800,000, and is - along with Abyan - set to host the Gulf Football Championship between November 22 and December 5.
Al-Rimi compared AQAP's fight to apply Islamic sharia law in Yemen with similar efforts by the Taliban in Afghanistan and Al-Shabaab in Somalia.