Yemen's army shelled Al-Qaeda hideouts in the southern city of Zinjibar, one of the jihadists' major strongholds, killing six militants, a local official told AFP on Monday.
The official, speaking from the nearby town of Jaar where wounded militants and dead bodies from Zinjibar are usually taken, said that "a Somali group leader named Abu Bilal" was among those killed in the late Sunday assault.
Witnesses and security services said that "dozens" of Somalians have been seen fighting in the ranks of Al-Qaeda in the Arabian Peninsula, the local branch of the jihadist network.
On February 23, the commander of the African Union forces in Mogadishu, Ugandan Major General Fred Mugisha, said that large numbers of Somalia's Al-Qaeda allied Shebab fighters -- close to collapse -- are fleeing the war-torn country for Yemen.
The extremists in Yemen, who go under the name Partisans of Sharia (Islamic law), have been locked in battles with the army in Abyan's provincial capital Zinjibar since May 2011, when they overran the city.
The Partisans of Sharia have exploited a central government weakened by a year of anti-regime protests to strengthen their position, launching deadly attacks against security forces especially in the lawless south and southeast.
State news agency Saba reported that US State Department counterterrorism coordinator Daniel Benjamin met with Yemeni Interior Minister Abdelqader Qahtan in the capital Sanaa on Sunday.
They discussed "means of strengthening and developing cooperation and security coordination between Yemen and the United States especially in terms of combatting terrorism," Saba said.
They also discussed "the form of support the United States could offer Yemeni security services in terms of combatting terrorism and organised crime."
The United States says the Yemen-based Al-Qaeda in the Arabian Peninsula, or AQAP, is the most active branch of the global terror network.
In February, former president Ali Abdullah Saleh, a self-declared US ally in its "war on terror", finally quit after 33 years in power handing power over to to his ex-deputy President Abdrabuh Mansur Hadi.
But since Hadi took office vowing his government would continue to battle Al-Qaeda, the Islamists have intensified their attacks against Yemeni forces.
On Sunday, the militants killed seven policemen in an attack on a checkpoint in the southeast while clashes between the army and the Islamists a day earlier left 40 dead from both sides.
Last month, 185 soldiers were killed in a massive assault by Al-Qaeda militants on an army camp near Zinjibar.