QUITO, Oct.  24 (Xinhua) -- At least four people were killed on Sunday by an avalanche on the  Chimborazo volcano in central Ecuador, said the country's Integrated Security  Service ECU 911.

The  avalanche fell on a group of 12 hikers as they were climbing the volcano at an  altitude of about 6,100 meters, the agency said in a statement.

After the  incident reported at 06:30 local time (1130 GMT), the Special Operations Group  of the National Police, the local fire department and a police helicopter were  sent to rescue the hikers, whose nationalities have not been revealed.

The access  to the Chimborazo Fauna Production Reserve, which surrounds the volcano, has  been suspended.

Chimborazo  is the highest volcano and mountain in Ecuador, with a height of 6,263 meters  above sea level. Its snow-covered peak is a popular summit for local and foreign  climbers.