Six Yemeni soldiers were killed early Monday in an ambush by suspected Al-Qaeda militants in the southern province of Hadhramaut, according to a security source."Militants believed to be affiliated to Al-Qaeda ambushed an army patrol in Hadhramaut, killing six soldiers," the source told Anadolu Agency requesting anonymity.No group has claimed responsibility for the attack.Yemeni authorities are yet to comment on the report.Four Yemeni anti-terror troops were killed and two others wounded on Saturday when their patrol was attacked by suspected Al-Qaeda militants in Ataq, a city within the southern province of Shabwah.Yemen has started hitting hard at Al-Qaeda in its southern provinces since late April.Battles between the army and Al-Qaeda in the southern provinces of Shabwah and Abyan left 500 Al-Qaeda militants and 40 Yemeni troops dead, the spokesman of the Yemeni army said in early May.Security remains to be a major challenge in Yemen, which has descended into chaos since a popular uprising in 2011 and regime change in 2012.