Lebanon's army on Sunday announced a pause in its offensive against Islamic State group militants along the mountainous border with Syria to allow for negotiations on troops held hostage since 2014.

The unilateral ceasefire came into effect at 7:00am (0400 GMT) and would "make way for the last phase of negotiations linked to the fate of the kidnapped soldiers," the army command's statement said.

Nine soldiers are believed to still be held by IS after militants overran the town of Arsal along the Lebanese border in August 2014.