ISLAMABAD - Two American climbers have gone missing while attempting to summit a mountain in northern Pakistan, officials said Thursday, as bad weather hampered rescue operations.

Kyle Dempster and Scott Adamson began their ascent of Ogre-II, a 7,285-metre (23,900-foot) peak off the Choktoi Glacier in the Gilgit-Baltistan region of Pakistan on Sunday August 21, according to a website set up to raise funds for their rescue.

"They planned on five days for the climb and descent. On Monday evening, their Pakistani cook, Ghafoor Abdul, spotted their headlamps roughly halfway up the peak," the page, which was posted on Thursday, said.

"The weather remained good until Tuesday afternoon (23/8/2016), when a storm moved in. Snowfall and cloudy conditions have persisted in the region since then.

"Kyle and Scott have not been seen since Monday, August 22, no surprise given the complexity and scale of the terrain and the vagaries of the weather."

Mohammad Iqbal, a local administration official, told AFP the government had not been able to call in helicopters so far because of adverse weather conditions, but "we will try if the weather gets better today".

He added: "A team of local high-altitude rescuers has been searching for them for the past three days but bad weather is preventing them from ascending."

A member of the Gilgit-Baltistan council that deals with expeditions in the area said they had contacted the army for help.

Pakistan has long been a draw for foreign climbers lured by some of the most spectacular mountains on Earth, including the savage K2, the world's second highest peak.