The army did not mention whether the ceasefire would include the Syrian side of the border where the "Hezbollah" group and Syrian regime forces were battling ISIS in the al-Qalamoun region.
"The army command announces a ceasefire beginning at 7:00 am (0400 GMT) to make way for the last phase of negotiations linked to the fate of the kidnapped soldiers", it said in a statement on Sunday. The Lebanese army has claimed that the intention of signing a ceasefire truce was to sit down for negotiations to search for its missing soldiers.
Hezbollah, a militant and political group, has been fighting ISIS on the Syrian side of the border in the West Qalamoun region.
It is believed that the Lebanese army is searching for information for its missing troops, MiddleEastEye reports.
Syrian state media, citing a military source, said a deal had been reached to move Islamic State militants to eastern Syria. The deal allows the extremists to surrender and be transferred to ISIL-held parts of eastern Syria.
Hezbollah and its allies have been pressing the Lebanese state to normalise relations with Damascus, testing Lebanon's official policy of neutrality towards the conflict next door.
The battle began a week ago when the Lebanese army, and Hezbollah together with Syrian government forces, launched separate but simultaneous assaults.
The Lebanese Army, now locked in combat with ISIL on its border with Syria, has paused in what it calls the "final phase" in its offensive to destroy the Islamic extremists.More news: Najma welcomes SC decision on Triple Talaq
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The fate of the nine soldiers held by ISIS has been unknown since 2014.
ISIL kidnapped 30 soldiers and policemen, of whom four were killed and one died of his wounds.
After months of fraught negotiations, Al-Nusra handed over 16 of the soldiers and police in December 2015 in exchange for the release of prisoners from Lebanese jails and delivery of aid.
Talks have begun with mediation by the head of Lebanon's internal security agency, a security source said. By late afternoon, however, there was still no word. Daesh controls most of the oil-rich province. They were still wearing their military uniforms, he said.
"We heard about some Syrians that escape from Lebanon to Syria and then they will enter Lebanon again after shaving their beards", said Basheer Matar.
IS has claimed several attacks in Lebanon in recent years, including twin bombings in a densely populated Beirut suburb that killed 44 people.
Lebanese soldiers return from an offensive against the ISIS on the border with Syria, August 21, 2017.
"That is the job of the Lebanese government", Mr Matar said.