Battling harsh weather, poor visibility and the limits of the human body, Pakistani climbers Sirbaz Khan and Naila Kiani on Monday summited the sixth tallest mountain in the world, Cho Oyu in Tibet, the Alpine Club confirmed.
Young mountaineer Shehroze Kashif is set to attempt to climb to the summit tomorrow.
In a message from Alpin Club Secretary Karrar Haidri on Monday afternoon, Sirbaz scaled the 8,188 metre-tall mountain in just over 28 hours.
What made his accomplishment even more amazing was that he completed the climb in marathon alpine style, without using fixed ropes or supplemental oxygen (like he has done on 12 other mountains taller than 8,000 metres).
"We salute his tenacity and skill as a mountaineer," the Alpine Club said in a message.
The summit of Cho Oyu is the 13th mountain taller than 8,000 metres, which he has summited, putting him in pole position to become the first Pakistan to climb all 14 mountains with peaks above 8,000 metres.
The only mountain left on his list is the 14th highest mountain, the 8,027-metre Shishapangma, also located in Tibet.
A short while after Sirbaz made it to the summit, Pakistan's premier female climber, Naila Kiani, reached the top of Cho Oyu.
"Her determination is truly awe-inspiring, as she conquered the peak in incredibly challenging conditions with very poor visibility and hostile weather," read the statement from the Alpine Club confirming her summit.
Like Sirbaz, Naila also mounted a marathon mountain climb that lasted over 28 hours.
"[The climb is] a testament to her strength and mountaineering skills."
Monday's feat is Naila's 10th summit, only four shy of completing her set of 8,000-metre peaks.
"Their dedication to mountaineering is truly commendable, and their achievements are a source of inspiration to all," he said while congratulating them on their success and prayed for their safe return down the mountain.
"Pakistan is proud of their accomplishments, and it is a time to celebrate."
Meanwhile, Shahroze Kashif, who has been in a race with Sirbaz to become the first Pakistani to climb all 14 mountains higher than 8,000 metres, arrived at Cho Oyu on Sunday after racing across Tibet in a day.
Before Sirbaz's summit on Monday, he and Shehroze were tied at 12 peaks.
Even if Sirbaz clinches the crown as Pakistan's most prolific climber, Shehroze can still claim to being the youngest-ever climber to conquer all 14 mountains.
Shehroze needs to summit Cho Oyu and Shisapangma to complete his set.