Samir Z., a French national who was born in 1995, was stopped at Brussels airport at 4:30 a.m. local time Sunday (10:30 p.m. ET Saturday) while trying to board a flight to Morocco, Belgian Prosecutor Eric Van der Sypt said in a statement.
"He is considered to be part of the entourage of Bilal Hadfi," according to Van der Sypt, referring to the 20-year-old so-called "baby-faced bomber" who blew himself up outside an international soccer game in the French capital after failing to gain access to the stadium on November 13.
Samir Z. was also suspected of attempting to leave for Syria twice this year, Van der Sypt's statement added.
He had yet to be charged Thursday but a court extended the time officials were able to detain him for questioning.
The second man, a Belgian national identified only as Pierre N. and who was born in 1987, was arrested less than two hours later at his home in the Molenbeek area of Brussels.
Both men were taken into custody on suspicion of participating in the "the activities of a terrorist organization," the statement said.
The arrests take the number of people detained in Belgium in relation to the Paris attacks to eight. Two of the other suspects are accused of ferrying Salah Abdeslam — the suspected attacker who has not been apprehended despite a Europe-wide manhunt — from Paris to Belgium after the killings.