CAIRO, Egypt – Fire ravaged a 19th century palace used by the upper house of Egypt's parliament Tuesday, with flames bursting through windows as helicopters scooped water from the Nile River to douse the blaze.

Flames soared upward from the top floor of the three-story building, and much of the interior appeared gutted. While firefighters focused on one corner of the building, the blaze burned unabated on the other side, spreading to the second floor with periodic explosions and showers of sparks.

Thick black smoke billowed over downtown Cairo, and rush hour traffic gridlocked from the dozens of fire trucks that rushed to the scene. But only three trucks were hosing down the building hours after the fire erupted, apparently due to water shortages.

Two helicopters ferried buckets of water from the Nile and poured them onto the blaze, without any immediate effect.

There was no official word on the cause. Evacuated employees said authorities told them they had ruled out terrorism, and that an electrical short-circuit had likely sparked the fire.

At least 16 workers and firefighters were hospitalized for smoke inhalation, said Ahmad Salah, the fire operations supervisor.

Riot police created a cordon outside the parliament complex, located on a busy downtown thoroughfare. Tourists and locals stopped to snap photographs with cell phone cameras.

Parliament's archive room, library and several large meeting chambers were all destroyed. Firefighters doused surrounding buildings with water to prevent them from igniting, but flames continued to rage past midnight.

Egypt's upper house of parliament or Shura Council is a largely symbolic body that can only advise on legislation. A third of its members are appointed by the president. Parliament is currently in summer recess.

Egypt requires some fire-safety measures in buildings, including fire extinguishers, but in general the rules are not strictly enforced.

The country's deadliest blaze was in February 2002, when flames swept through a crowded passenger train south of Cairo, killing 370 people.