The two men and two women were due to return to base camp in late October after climbing the 6,079-metre (20,060-feet) high Renzhong Mountain in Sichuan province, Lin Li, head of the Sichuan Mountaineering Association, told AFP.

But Lin said emergency rescue efforts were launched when they failed to turn up.

"On November 4, the rescuers reached 4,400 metres, but they did not find the missing people, although they saw some signs of avalanches and icefalls -- the rescuers are continuing to search for them," he said.

Peter Sarkozy, the Hungarian consul general, told AFP the four were professional mountaineers.

"The relatives back in Hungary are worried and we are in permanent contact with them," he said.

This is the second time in less than a week that climbers have gone missing in the same area of western Sichuan, home to a number of mountains that attract climbers from around the world.

On October 28, four Russians were caught in an avalanche on Four Girls Mountain in Aba county. Two survived but the others, a couple, were buried and are presumed dead.

"We dispatched over 100 people to search for them, but we did not find them," Lin said, adding the Russian climbers did not obtain permission to climb the mountain.

"Then the two survivors asked us to stop the search programme... so the rescue work has been suspended."

"It's a dangerous activity, which could easily be affected by natural disasters like earthquakes and snowslides," Lin was quoted as saying in the official Global Times newspaper.

The onset of winter and last year's 8.0-magnitude earthquake, which hit Sichuan province in May leaving more than 87,000 people dead or missing, were factors increasing the possibility of accidents, he added.

All rights reserved. © 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.