Police in Turkey have found modelling clay inside the package that two men, who had hijacked a plane from Cyprus, said contained explosives.
The two men hijacked a Turkish passenger plane but later surrendered after it landed in Antalya in southern Turkey.
One of the men is believed to be Turkish and the other was carrying a Syrian passport.
Turkish police also detained a third person as a suspected accomplice of the hijackers, who left the plane together with passengers who managed to escape after the aircraft landed.
Police are still investigating the motives of the hijackers and declined to comment on reports that they were members of al Qaeda.
According to passenger accounts, the two men said they were members of the terrorist network and had a package that they claimed to be a bomb.
There were 136 passengers and crew on board when the plane made an emergency landing.
Most of those on board managed to escape, including the pilots, but the hijackers held six people on the plane for a time.
The two hijackers reportedly wanted to take the plane to Iran but the pilot was believed to have told them they needed to refuel.
The Iranian foreign ministry has condemned the hijacking and said it would have rejected the hijackers' request to land in Iran.
The plane, operated by the private Turkish airline company Atlas Jet, was flying from northern Cyprus to Istanbul.
