Tommy Caldwell, 36, and Kevin Jorgeson, 30, made 'great progress' as they became the first to climb El Capitan's so-called Dawn Wall without bolts or climbing tools, spokeswoman Jess Clayton said.

Caldwell and Jorgeson, who began their climb on December 27, are expected to celebrate privately with their families at the summit before speaking to reporters in a Yosemite meadow on Thursday.

A tweet on Jorgeson's account on Wednesday read: 'It's not over till it's over. #DawnWall' 

The Dawn Wall of El Capitan is divided into 32 climbing pitches, which are varying lengths of rock that the climbers are trying to master with only their hands and feet. 

The wall has been scaled before, first by legendary climber Warren Harding in 1970, but never before without climbing tools.

Caldwell and Jorgeson had reached the final 11 pitches on Tuesday after working their way past some of the toughest stretches on the rock.

Jorgeson struggled for several days last week on difficult pitch 15, at one point being forced to rest for two days while the skin on his fingers healed after being ripped off by razor-sharp ledges.

The two climbers are using safety ropes in case of falls, and using ropes and other tools to move back and forth from their campsite perched high on the rock.

Because the warmth of the day can cause their hands and feet to perspire, the two often start climbing at dusk.

Caldwell and Jorgeson's attempt on El Capitan has been closely watched in the climbing world and has drawn worldwide news headlines and attention on social media as they made progress toward the summit.

According to Brandwatch, a social listening and analytics firm, social media mentions of the climb have skyrocketed since the climb began, drawing more than 17,000 mentions as of Wednesday.

(dailymail.co.uk)