ADEN, Yemen, Sept. 9 (Xinhua) -- Two children were killed and three others injured in a roadside bomb blast in Yemen's southern province of Lahj on Monday, a security official told Xinhua.

"A roadside bomb exploded near a residential building in downtown Lahj province, leaving two children killed and three others injured in the area," said the official on condition of anonymity.

He said that "all the victims were members of one family and accidentally walked through a roadside bomb placed near their house."

"Terrorist elements were apparently planning to target a security commander living in the same neighborhood," he added.

Witnesses told Xinhua that the roadside bomb caused a huge explosion in the center of Lahj province.

Landmines and explosive devices have been claiming civilian lives in Yemen, especially in the southern areas liberated from the Iranian-backed Houthis.

Yemen has been locked into a civil war since late 2014, when Shiite Houthis overran much of the country and seized all northern provinces, including the capital Sanaa.

The fifth-year civil war has killed more than 10,000 people, mostly civilians, displaced 3 million others, and pushed Yemen to the brink of famine.