The Lebanese military announced on Sunday a ceasefire in its battle against ISIL along the north-east border with Syria to allow for negotiations on nine soldiers held hostage by the extremists.
Nusra militants and a Syrian rebel group withdrew from Lebanon's border region earlier this month.
Hezbollah engaged in the talks with the IS without mandate from, or coordination with the Lebanese government but any deal with the group must be approved by Syria, he added.
Al-Ikhbariya, a Syrian TV station, said a Hezbollah delegation arrived in Syria to evacuate the bodies of Lebanese soldiers, but there was no official statement on the matter.
It is believed that the Lebanese army is searching for information for its missing troops, MiddleEastEye reports.More news: FM says Iraqi forces have taken 70 percent of Tal Afar
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.
The security source said on Sunday that Hezbollah entered an area in western Qalamoun to confirm if the Lebanese soldiers were buried there. The fate of nine soldiers that Islamic State took captive then remains unknown.
The government-controlled Syrian Central Military Media and the opposition's Britain-based Syrian Observatory for Human Rights said Syrian troops have now surrounded an area of 2,000 square kilometers (772 square miles) in the Syrian desert, widely referred to as Badia.
The joint-offensive began last week when the Lebanese army and the Hezbollah, along with their Syrian allies, liberated a vast portion of land which was previously under the Islamic State's control.
Hezbollah has been fighting in Syria alongside President Bashar Assad's forces since 2013.More news: American service member missing after Black Hawk helicopter crashes off Yemen's coast
The Lebanese army has said it is not coordinating its attack with the Syrian army or Hezbollah, which Washington classifies as a terrorist group.
Lebanon's defence minister said in comments to reporters that Hezbollah was carrying out the negotiations over the soldiers, who were captured in 2014 when al-Qaeda and ISIS militants briefly overran a Lebanese town near the border.
Lebanese soldiers return from an offensive against the ISIS on the border with Syria, August 21, 2017.
The Lebanese army has been battling ISIL fighters in their last border foothold, near the town of Ras Baalbek.More news: 'The Batman': Everything You Need To Know About The DC Film