Lava flowing from Piton de la Fournaise on Reunion

Raging lava has spewed out of one of the world's most active volcanos on the French island of La Reunion.

The red hot lava cut roads in half, damaged homes and created huge clouds of steam as it flowed into the Indian Ocean.

But the islanders are used to the spectacle. It is the third eruption of the Piton de la Fournaise or 'Mountain of the Furnace' this year alone.

About 50 teenagers were taken to hospital from three schools in Saint Joseph with respiratory problems caused by the volcano's sulpher fumes, according to, the online newspaper of La Reunion.

Researchers on the island are concerned the recent activity may be creating more cracks lower down the volcano, which will allow the molten lava to spread further.

The volcano is about 530,000 years old and has erupted an estimated 170 times since the mid 17th century.

La Reunion is a small island wedged between Madagascar and Mauritius. It is one of twenty-six regions of France and President Jacques Chirac is the head of state.

The 777,000 island inhabitants once prospered from the cultivation of sugar cane, but tourism and financial aid from Paris now underpin its economy.