Abbachi was placed under preventive arrest and Romanian authorities started procedures for his extradition to Italy, police said.
Abbachi is married to a Romanian woman living in Galati town, eastern country.
Abbachi’s apprehension is part of a wide investigation unfolded by Italian authorities.
Two weeks ago, Italian daily Il Secolo XIX said that Italian police obtained, after intercepting a telephone conversation between two terrorism suspects, indications on the existence of al-Qaeda training camps in Romania, from where terrorists might easily reach Western Europe.
It said investigators intercepted a conversation between two terrorism suspects – Tunisians Jameleddine Ben Mohamed Ben Moussa and Bechir Kaouana – who mention the existence of " al-Qaeda training camps in Romania," where jihad warrior wannabes learn how to build and use explosive devices.
Romanian authorities denied all allegations.