A security official was killed by unknown gunmen Monday in Yemen’s Ibb province.

A security official was killed by unknown gunmen Monday in Yemen's Ibb province, a security source said.

The assailants opened fire on Col. Abbas al-Maghribi as his car passed by near Ibb University in the city bearing the same name of the province, the source, who requested anonymity, told media outlets.

"They shot the security official in the head, which led to this immediate death," the source said, adding that the gunmen "fled the scene after the attack."

The attack has yet be claimed by any group.

Yemen has been dogged by turmoil since pro-democracy protests forced autocratic president Ali Abdullah Saleh to step down in 2012 after 33 years in power.