The footage shows what is described as Islamic State fighters boarding vehicles and driving towards the last IS-held city in Iraq, Rawa, which is located around 50 miles west of al-Qaim.
Hezbollah was "the foundation in the battle of Albu Kamal", said the commander, adding that hundreds of the elite forces of the Iran-backed Shi'ite group took part in the battle.
Al-Manar TV, the media arm of the Lebanese Hezbollah group, said Wednesday that troops have surrounded the eastern town of Boukamal, on the border with Iraq.
REUTERS/Sabratha municipality media office/HandoutA view shows damage at the scene after an airstrike by USA warplanes against Islamic State in Sabratha, Libya, in this February 19, 2016 handout picture.
The Hashed al-Shaabi paramilitary alliance has denied that its own forces entered Syria on Wednesday as part of the fight.
In recent weeks, an estimated 120,000 people have been displaced from Albu Kamal alone, said Linda Tom from the United Nations' humanitarian affairs coordination office in Damascus.
Despite its losses, Islamic State still has a territorial presence in Libya and elsewhere, and many governments expect it to remain a threat even after it loses the caliphate it declared from Mosul, Iraq, in 2014. News showed ISIS fighters attempting to flee al-Qaim city.
The city of Deir ez-Zor, which endured years of IS blockade, was breached by the Syrian army with the support of Russian airstrikes early in September.
According to USA Today, the ISIS previously roamed the cities of Iraq and Syria riding in tanks and presenting themselves as an easy target for US -backed coalition airstrikes.
More than 330,000 people have been killed in Syria since the conflict began in March 2011 with anti-government protests, before spiralling into a complex, multi-front war that drew in global forces and jihadists.