Convoys of buses arrived on Monday to transfer thousands of Syrian militants and refugees from Lebanon's border region into rebel territory in Syria in exchange for Hezbollah prisoners.
Under a local ceasefire between the Sunni Muslim militants with links to al-Qaeda and the Shia Hezbollah, about 9,000 fighters and their relatives were to leave.
With no sign of any buses leaving, the departure was delayed to Tuesday from Monday for “logistical” reasons including having to wait for the rest of a total of 98 coaches to arrive from the Syrian side, a Hezbollah media unit said.
The deal includes the departure of all Nusra Front militants from Lebanon's border region around the town of Arsal, along with any civilians in nearby refugee camps who wish to go.
The truce echoes deals struck within Syria in which Damascus has shuttled rebels and civilians to Idlib province and other opposition areas. Such evacuations have helped President Bashar al-Assad recapture several rebel bastions over the past year.
Lebanon's Hezbollah has played a major role in fighting militants along the frontier during Syria's six-year war, sending thousands of combatants to support Assad's government.
Last week, Hezbollah took most of the mountainous zone of Jroud Arsal in a joint offensive with the Syrian army to drive Nusra militants from their last frontier foothold.
The Nusra Front was al-Qaeda's Syria branch until it severed ties and rebranded last year. It now spearheads the Tahrir al-Sham Islamist alliance in the Syrian war.
The Lebanese army, which receives considerable US and British military support, did not take an active part in the operation, setting up defensive positions around Arsal.
The next phase is expected to target a nearby enclave currently in the hands of Islamic State jihadists.
“Buses that will transport Nusra Front militants and their families have started arriving in Jroud Arsal,” the military media unit run by the Iran-backed Hezbollah said via social media on Monday.
The convoys rolled in from Syria and headed towards Lebanese army positions. Syrian Red Crescent ambulances arrived on the opposite side of the frontier, the media unit said.
Footage from the border zone showed dozens of white buses driving through the barren hills. The Lebanese Red Cross has taken part in logistics.
The first step of the ceasefire, brokered by Lebanon's internal security agency, unfolded on Sunday as the two sides exchanged the bodies of dead fighters.