VALENCIA, Spain (CNN) -- A Spanish jetliner with 131 people aboard was hijacked Tuesday and forced to land in the coastal city of Valencia, where ground troops were "taking necessary steps," the prime minister's office told CNN.

Three armed hijackers took Iberia Airlines Flight 1121 captive on a domestic flight from the southern city of Seville to Barcelona. Spanish media said 124 passengers and seven crew members were on board.

One Spanish report said the mayor of Seville was a passenger, but the office of Prime Minister Jose Maria Aznar could not immediately confirm that.

Shortly after landing, eight children and three elderly passengers were released unharmed, Spanish media reported.

The Boeing 727 was diverted to the eastern city of Valencia, where it landed around 8:40 a.m. (0640 GMT/2:40 a.m. EDT) apparently for refueling, Spanish media reported. Conflicting reports said the hijackers, whose nationalities were not immediately known, were demanding to be flown to Athens or Tel Aviv.

Aznar's office said a variety of special forces were being moved into place "taking necessary steps" to possibly end the crisis.

No further details were immediately available.