By Aijaz Mahar
BBC News, Islamabad
Four Russian mountaineers have gone missing in Pakistan on the world's second highest mountain, K2.
Many experts say K2 is a tougher climb than Everest
The four climbers, who disappeared on Sunday, were part of a 10-member international expedition.
Three injured French climbers from another expedition had to be evacuated by military personnel from another mountain in northern Pakistan.
The two expeditions faced treacherous weather. Many experts regard K2 as a more perilous climb than Everest.
The team trying to scale the 8,611m (28,251ft) K2 - also known as Mount Godwin Austin - consisted of eight Russian, one Irish and one Polish climber.
They were beaten back by severe weather. The leader of the expedition is among the missing climbers.
The team was on its way back from its last camp when the four went missing, said Naiknam Karim, an official with the company organising the climb.
He also said there was an avalanche on the mountain but it is not clear whether the climbers were hit by it.
Rescue helicopters were not able to go on a search due to bad weather, Mr Karim said.
Meanwhile, the nine-member French expedition team was on its way to the summit of 16,000ft Talkash Glacier in northern Ghizer district when three climbers went missing, district officials said.
But the three injured climbers, including a woman, were safely evacuated from a deep ditch by the army after a two-hour search.
Local officials say the team was hit by an avalanche on Tuesday.
Hospital sources in Gilgit, where the climbers were admitted, say the woman climber is seriously injured while the others sustained minor injuries.