Al-Qaeda in the Arabian Peninsula (AQAP) fighters have consolidated their grip on territory in southern Yemen after capturing the towns of Zinjibar and Jaar from pro-government forces.
The AQAP fighters launched an offensive on the towns at dawn on Wednesday, local officials said.
Al-Khader Haidan, a leader within the popular committee forces in Zinjibar district, told Al Jazeera that the attack had been expected and that AQAP fighters had been planning to take over Abyan governorate, where both towns are located, since pro-government forces captured it from Houthi fighters in July.
"Abyan is a stronghold of AQAP and we already informed the authorities in Aden to send us military reinforcements, but we did not get enough support from the Yemeni army," he said.
"That is why the AQAP fighters took over the two main districts in Abyan easily."
Zinjibar, the capital of Abyan province on the Arabian Sea, had been a major focus of forces battling the Houthis.
It was the fourth regional capital they had won back after taking control of the port of Aden from the Houthis in July.
The war in Yemen is being fought on multiple fronts, with a large number of formal and informal forces squaring off in various areas of the country.
President Abd-Rabbu Mansour Hadi, backed by a Saudi-led coalition and a number of popular committee forces loyal to his government, are locked in an ongoing struggle for territory with the Shia Houthi rebels and their allies - who seized the capital Sanaa last year.
READ MORE: Anti-Houthi fighters 'seize Zinjibar city in Yemen'
In the south and east, however, AQAP has taken advantage of fighting elsewhere to consolidate and expand on its own territory.
Bashraheel Hisham Bashraheel, deputy editor of the Yemeni Al-Ayyam newspaper, told Al Jazeera that AQAP has increasingly taken over more areas in Abyan over the past month, without facing much resistance.
"The Houthi rebels are now saying they are going to march down towards these areas," he said, adding that government forces will have a "huge task" to separate the different fighting factions.
Fadhl al-Rabei, a political analyst and head of Madar Studies Centre in Aden, told Al Jazeera that it appeared AQAP was likely to take control of all of Abyan province.
Rabei said it appeared that the popular committees may have ceded Zinjibar and Jaar as a way of pushing the Yemeni government forces to join their fight with AQAP.
"There is coordination between AQAP in Abyan and the popular committees, and when the popular committees want something from the government they allow AQAP fighters to take over areas in Abyan," he said.
Elsewhere on Wednesday, locals told Doctors Without Borders (MSF) that an air strike had hit one of its mobile clinics in the al-Houban area near Taiz - injuring seven people.
"Our teams are still collecting more information about the incident and providing treatment to wounded people who were caught in the air strikes," MSF said in a statement.
The Saudi-led coalition launched the military campaign against the Houthis in March with the aim of restoring Hadi's government after the rebels captured large parts of the country.
At least 5,400 people have been killed, and at least 1.5 million people have been displaced since the war began.
Source: Al Jazeera