Lyon (AFP) - A late-season avalanche killed two skiers and their guide in the French Alps near the Italian border Tuesday, local officials said.

The avalanche struck in the Albaron area, the mayor of nearby Bonneval-sur-Arc, Gabriel Blanc, told AFP.

"We know from a reliable source that there were only three" victims, Blanc added, after the local government said a search was continuing for more possible victims.

The three were headed towards the Greffier pass, the mayor said. Authorities do not know what caused the avalanche.

All three were in their 30s and came from the region.

They had begun scaling the Vallonet glacier with their skis on their backs when the avalanche struck at an altitude of some 2,800 metres (9,200 feet), local police chief Emmanuel Duboft told AFP.

The block of snow, between 100 and 200 metres wide, "knocked them off-balance and they hit several rocky ridges," he said.

Another climber nearby raised the alarm.

Because the victims were not buried in the avalanche their bodies were quickly found and taken by helicopter to a temporary morgue in Bonneval-sur-Arc.

Three Dutch snowboarders in their 20s were killed when they were swept away by an avalanche in an unmarked area near the Valfrejus resort, in the same area, on March 7.

Duboft, noting that five snowboarders had narrowly escaped serious harm by an avalanche in the region on Monday, said: "People should keep an eye on weather conditions. It snowed a lot last week and some places are still avalanche-prone."