A photo of Lebanese soldier Atef Saadeddine taken from the YouTube video he appeared in.
A Lebanese soldier has defected to an Al Qaeda group in neighbouring Syria, in the first such incident, in protest at what he said was the injustice against Sunni Muslims in his country.
A Lebanese security source said the army considered the Sunni Muslim soldier a deserter but there was no official comment from the army, which groups soldiers from all sects.
Security sources said Atef Saadeddine, 23, went missing on Tuesday while on duty at a checkpoint near the Syrian border.
On Wednesday, Saadeddine appeared in a YouTube video, which showed him wearing his army uniform with the black flag of the al-Nusra Front, al Qaeda's affiliate in Syria, in the background and two guns propped up against a wall.
"I am the defected soldier Atef Saadeddine from the 8th division," he said, showing a military identification card with his picture on it, issued by the Lebanese Ministry of Defence.
The video ended with him embracing five masked armed men who all kissed his forehead as a welcome sign.
The Syrian civil war has aggravated deep-rooted sectarian tension in Lebanon, with Sunni Muslims supporting rebels against President Bashar al-Assad and the Lebanese Shi'ite Muslim group Hezbollah fighting alongside Assad's army.
Saadeddine said Sunnis were facing "harassment" by the army, which he accused of working under the command of Hezbollah, and carrying out arrests and raids at the group's request.
He accused Hezbollah of killing Sunni Muslims in Lebanon and Syria.
In the past months, there has been a rise in attacks by armed men believed to be Sunni militants against Lebanese army soldiers and checkpoints, killing several of them mainly in north and east Lebanon.
© Thomson Reuters 2014