Gunmen have killed 10 people, including at least nine foreign tourists, after storming a hotel in northern Pakistan.
The nationalities of the victims have not been fully confirmed, although they include a number of Ukrainians and Chinese. One Pakistani also died.
The assault happened at the base camp of Nanga Parbat, the world's ninth highest mountain, in Gilgit-Baltistan.
It is the first such attack on tourists in the region. The Pakistani Taliban has told the BBC it was responsible.
A spokesman for Tehrik-e-Taliban said the attack was in retaliation for the killing of its second-in-command, Waliur Rehman, who died in a suspected US drone strike in May.
The group said it would continue to target foreigners.
An adviser to the Gilgit-Baltistan government told the BBC that helicopters had been sent to evacuate the remaining climbers in the region - believed to number between 20 and 25.
Part of the Himalayan Range, Nanga Parbat, which stands at 8,126m (26,660ft), is popular with trekkers and mountaineers, especially during June and July.
The assault is seen as a significant blow for Pakistan's already struggling tourist industry, the BBC's Shahzeb Jillani reports from Islamabad.
The number and nationalities of the victims have not been made fully clear.
Two Chinese, one Chinese-American, one Nepali and a Pakistani have been confirmed dead by local and interior ministry officials.
Five bodies remain to be identified, most are believed to be of Ukrainian tourists.
A Chinese tourist is known to have survived the assault.
The trekkers had planned to climb Nanga Parbat in the coming days, a local tour operator said.
Up to 20 attackers, reportedly dressed in local paramilitary uniforms, stormed the hotel at the base camp in the foothills of Nanga Parbat at about 22:45 local time on Saturday (17:45 GMT).
The gunmen separated and tied up the local Pakistani staff and told them not to attempt to raise the alarm until morning, a local official said.
The gunmen then shot the foreigners, taking their money and passports.
The attackers left at about 01:00 on Sunday local time.
One person managed to get free and raise the alarm but the attackers had about six hours to make their escape.
The deputy commissioner of Diamir district told the BBC a manhunt was under way involving both police and military, on the ground and in the air.
Officials say given the terrain it would be easy to spot human movement from the air, but no arrests have yet been made.
President Asif Ali Zardari and Prime Minister Nawaz Sharif have condemned the attack.
Mr Sharif, who was re-elected earlier this month, said "such acts of cruelty and inhumanity" would not be tolerated.
Interior Minister Chaudhry Nisar Ali Khan said Gilgit-Baltistan's police chief and another senior official had been suspended.
Gilgit governor Syed Mehdi Shah said: "A lot of tourists come to this area in the summer, and our local people work to earn money from these people.
"This will not only affect our area, but will adversely affect all of Pakistan."
Gilgit-Baltistan is famous for its natural beauty and the main city of Gilgit is seen as a gateway to the Karakoram and Himalayan mountain ranges.