The two men accused of using fake weapons to hijack a Libyan plane earlier this week with 117 people on board before diverting it to Malta appeared in court Sunday.
Moussa Saha and Ali Ahmed Saleh pleaded not guilty in Valletta's law courts to a string of offences including hijacking a plane and threatening passengers.
If convicted they face maximum sentences of life in jail.
The Afriqiyah Airways Airbus A320 was en route from Sabha in southern Libya to the capital Tripoli when it was taken over and forced to fly to Malta, sparking a four-hour runway standoff.
While the two suspects were initially thought to have used a real grenade and at least one pistol to stage the hijacking, it later emerged that they had allegedly used fake weapons, a Maltese government statement said.
The pair were escorted into the Christmas Day hearing under heavy armed security and the two men were wearing bullet proof vests.
Through his lawyer, Moussa asked the court to allow him to communicate with his family and be allowed to pray. The presiding magistrate said usual practices and procedures should be followed.
Sources close to the investigation told AFP that the men refused to answer any questions during their interrogations. They were remanded in custody. The case continues.
Hijackings have become relatively rare since the September 11, 2001 terror attacks on the United States led to increased security on flights.