A clash between rebels leaving Aleppo and militias could have been the reason the evacuation from the Syrian city broke down today.
ITV News Correspondent Dan Rivers, one of the few western journalists in Aleppo, said rebels claim militias shot at their people as they were trying to evacuate, reporting four had been killed.
If confirmed, it would constitute a war crime, but Hezbollah denied that anyone had been killed in the incident.
Separately, a photo has also emerged showing people lying in the road, apparently being guarded by militia who were unhappy with the evacuation process.
"Clearly something went dramatically wrong today," Dan told ITV News at Ten.
But he said there was still hope of the deal getting back on track.
Tens of thousands of civilians desperate to leave Aleppo were left stranded for 48 hours over the weekend after a ceasefire deal broke down.
Dubbed the People's Convoy, aid workers intend to take medical supplies to a new children's hospital in Syria.
Watch all of ITV News correspondent Dan Rivers' reports on the end of the battle for Eastern Aleppo and the evacuation from the city.