Yemeni forces have launched an operation to drive Al-Qaeda fighters out of southern towns, where air strikes killed nearly 60 militants last week, military officials said on Tuesday.
Al-Qaeda in the Arabian Peninsula jihadists established strongholds in towns and rugged zones in Abyan and Shabwa provinces after security forces chased them from major cities in Abyan in 2012.
Yemeni and US drone strikes last week targeted bases of AQAP, considered by Washington as the most dangerous affiliate of the global jihadist network with links to several failed terror plots against the United States.
Army troops backed by local militiamen had moved in to "purge" the Abyan towns of Ahwar and Al-Mahfad, and Azzan, Al-Houta, Al-Rawda and Al-Saeed in Shabwa province, a military official told AFP.
"The campaign will not stop until these areas are purged of Al-Qaeda militants," added the official, who was speaking on condition of anonymity.
Government forces clashed Tuesday with Islamist militants in the Lahmar area, which overlooks Al-Mahfad, a military commander said.
Other confrontations took place near Al-Saeed as militants took on advancing government forces, other military sources said.
Hussein al-Wuhayshi, a leader of the Popular Committees armed groups that had fought in the past alongside government forces, said his forces were taking part in the attack.
"There is an official decision to uproot Al-Qaeda from Abyan and Shabwa," Wuhayshi told AFP.
- 'Strategy to restore security' -
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"This strategic aim shall not be abandoned until security and stability are restored," the general told a security meeting in Ataq, quoted by Yemen's official Saba news agency.
AQAP took advantage of the weakening of the central government in Sanaa after the nationwide uprising, establishing strongholds in the southern and eastern regions.
In June 2012, government forces backed by the Popular Committees drove Islamist militants out of major cities in Abyan after they had been in control for around a year.
Officials spoke last week of an "unprecedented" US and Yemeni aerial campaign against Al-Qaeda militants in the area after two days of strikes.
The interior ministry said last week that air raids on April 20 in Abyan province killed 55 militants, while three others were killed in a strike in Shabwa.
A day earlier, a drone strike in the central province of Baida killed 10 Al-Qaeda suspects and three civilians.
AQAP leader Nassir al-Wuhayshi pledged in a rare video last month to attack Western "crusaders... everywhere in the world".
The video, which showed Wuhayshi addressing militants, could have been shot in the Al-Kur mountain range, which stretches between Abyan, Shabwa and Baida provinces, and has become an AQAP stronghold, according to tribal sources.
US drones frequently strike suspected militants in the country despite mounting criticism from rights groups concerned about civilian casualties.
The United States has defended its use of drones against Al-Qaeda, saying they allow it to target jihadists without sending soldiers into lawless areas where local authorities have little or no control.