Three foreign climbers are missing and feared dead on Pakistan's treacherous Karakorum mountain range in the country's far north, an official said Thursday.
Pakistan is home to five of the world's 14 "super peaks" -- those over 8,000 metres (26,246 feet) high -- and the climbing season is currently in full swing.
A senior government official from the Gilgit Baltistan tourism department told AFP that Canadian Richard Cartier and Australian Matthew Eakin were missing on K2, the world's second-highest mountain, while Briton Gordon Henderson was lost climbing Broad Peak, the twelfth-highest.
"We cannot declare them dead until the bodies are found," the official said.
"We pray we find them alive, but the chances are very slim."
Henderson, a wing commander with Britain's Royal Air Force, went missing on July 19 on the 8,051-metre Broad Peak, the armed force said on its verified Facebook page.
"Our thoughts are with Wing Commander Henderson's family, friends and colleagues at this dreadful time," it said.
Eakin and Cartier have been missing since the weekend on K2, which is nicknamed the "Savage Mountain" for its high level of difficulty.
Records have tumbled this season, according to the Pakistan Alpine Club, with over 140 people summiting the 8,611-metre K2 -- including 20 women.
Until this year, it had been scaled just 425 times, whereas Everest -- the world's highest -- had been conquered by more than 6,000 people since Edmund Hillary and Tenzing Norgay first reached the top in 1953.
A video shared on social media by Nepali climber Mingma Gyalje earlier this week showed a long queue of tethered climbers pushing upwards on K2.
"This is the scariest part," he said in an accompanying caption on his Facebook and Instagram pages.
K2 earned its nickname because of its punishing conditions -- in winter, winds can blow at more than 200 kilometres per hour (125 miles per hour), and temperatures drop to minus 60 degrees Celsius (minus 76 Fahrenheit).
Last week, Sanu Sherpa, from Nepal, became the first person to complete the double summit of all 14 super peaks after he reached the top of Gasherbrum II in Pakistan.
Norwegian Kristin Harila, meanwhile, is attempting to break the record for climbing all 14 super peaks in the fastest time, taking on Nepali adventurer Nirmal Purja's record of six months and six days.
The 36-year-old scaled K2 on Thursday -- the eighth peak of the challenge -- on day 70 of her pursuit.