Two people were killed in Tripoli following overnight gunfighting between the two leading armed in Libya, officials said Tuesday. The city's only civilian airport was forced to shutdown. The fighting between the influential "444 Brigade" and the "Al-Radaa Force" (Special Deterrence Force), erupted on Monday night into Tuesday, an interior ministry official said. French news agency, the Agence France-Presse learned that "tension rose" shortly after it was announced that the Al-Radaa Force has arrested leader of the 444 Brigade, without explaining whether this was on judicial orders or for other reasons, the official said. The United Nations Support Mission in Libya, UNSMIL, said in a statement it was concerned about the security deterioration in the Libyan capital and its impact on civilians. "Violence is not an acceptable means to resolve disagreements," UNSMIL said.