A US citizen has been arrested in Tunisia after allegedly trying to travel to Libya in an attempt to join the IS (ISIS), US authorities said on Tuesday.

According to local US media, the man is 20-year-old Bernard Raymond Augustine, who was detained in Tunisia and then was returned to the US to face charges of attempting to provide material support to terrorism.

"Augustine was originally arrested in Tunisia 2016 where he arrived on a flight that originated in San Francisco." Local US media also reported.

Augustine told US Customs and Border Protection officials upon departure that his intention was to travel to Tunisia for vacation.

US media reported that investigators searched Augustine's computer and discovered messages that he allegedly sent to the IS group.

A song that praises the militant organization was also found on the computer, ABC reported.