In Sunday's attack, fighters are said to have fired a grenade on a police vehicle at a highway crossroads as officers were changing shifts, Liberte reported.


A second police vehicle came under machine-gun fire, Liberte reported, citing witness accounts.


Security forces dispatched reinforcements, prompting a two-hour fire fight.


It was not immediately clear whether any of the assailants were detained or injured.


There was no independent verification of the attack.