A mannequin stands near a face-painting stall at the Libya Comic Convention in Tripoli on November 2, 2017, ahead of its closure by an armed group

A Libyan armed group said Saturday it had closed a comic book convention in Tripoli and detained the organisers for an "attack on morals and modesty" in the strife-ridden country.

Hundreds of young Libyans on Friday flocked to the opening of the city's second Comic Con festival, including some dressed up as their favourite heros from American comic books and Japanese manga.

Later in the day members from the Deterrence Force -- a group of mainly conservative Islamists that acts as the police for the UN-backed government -- entered the venue, seized computers and arrested organisers, a participant said.

Libyans gather Comic Convention in the capital Tripoli on November 2, 2017, ahead of its closure by an armed group

The group said those responsible for the event would be handed over "to prosecutors for an attack on morals and modesty" as they looked to prey on youths in the city.

"This sort of festival imported from abroad exploits the weakness in their religious faith and their fascination with foreign cultures," said a statement posted on Facebook.

Comic Con began in 1970 as a convention of a few dozen fans who swapped superhero magazines in the United States.

The event has grown in size and spread around the world, including to ultra-conservative Saudi Arabia.

Artists draw manga-style during the Libya Comic Convention in the capital Tripoli on November 2, 2017, ahead of its closure by an armed group

Libya has been wracked by conflict since the fall of dictator Moamer Kadhafi in 2011 and the country has two rival governments: a United Nations-backed one in the west and a rival administration backed by a military strongman in the east.

Hundreds of different militia groups have stepped in to impose their authority in the security vacuum.