Update (7.48pm): It has now been confirmed that two French high school students and a Ukrainian skier have been killed after an avalanche in the French Alps.
Officials did not give any information on the number of missing but said 60 rescue workers have been mobilised in a search-and-rescue operation with sniffer dogs and a helicopter.
Earlier: An avalanche that struck a school group skiing in the Alps has killed at least one person and left three seriously injured.
French Police Commander Bertrand Host told BFM television that there had been an avalanche warning in the area before the snow slide.
Police say a search and rescue squad is on the scene, searching with dogs and a helicopter.
The avalanche struck late on Wednesday afternoon in the Deux Alpes region.
Citing local police, the regional Dauphine Libere newspaper is reporting that four of the students were found in cardiac arrest and the teacher was unconscious.
Venosc mayor Pierre Balme told the paper the avalanche occurred on a closed ski run.