Swedish prosecutors indicted Monday a former Syrian rebel accused of severely beating a pro-regime fighter in 2012 after a video of the attack was posted on Facebook.

The 28-year-old is accused of violating international law - including the Geneva Conventions which govern the treatment of prisoners of war - and of aggravated assault, in what is believed to be the first case in Sweden linked to the conflict in Syria.

A video of the beating posted on the defendant's Facebook account has been cited as evidence against the former Free Syrian Army fighter who has lived in Sweden since 2013.

"To my knowledge, there has never been a trial like this," prosecutor Henrik Soederman told AFP.

According to the indictment, the defendant participated in beating "an unidentified person tied to the Syrian state's armed forces" in the summer of 2012 in a manner that "resembles torture."

The victim - whose hands and feet were tied - had been injured before the assault, which included several blows with a whip and a truncheon or with similar weapons.

The former Syrian rebel said he had been forced to perform the acts.

He has been detained since October and a trial date has not yet been disclosed.

Prosecutors said they would seek his deportation and a ban on re-entry to Sweden.

The man arrived in Sweden in September 2013, the same month that Stockholm announced it would grant automatic residency to all Syrians fleeing the conflict, except those found guilty of war crimes.