It's not everyday that you bump into the US President while hiking up a mountain. But several surprised hikers did just that, as they crossed paths with Barack Obama and First Lady Michelle Obama, as they walked the Koko Head on Oahu's southeastern side with friends on Tuesday (22 December).

The Obamas were on their annual two-week holiday in Hawaii, when they were spotted on the grueling trail, sometimes referred to as 'The Stairmaster from Hell' or 'The Koko Head Stairs Of Doom'.

The President's motorcade passed the Koolau Mountains, Waimanolo Beach, Rabbit Island and Obama's favorite body surfing spot, Sandy Beach. As the motorcade made its way up a hill around Hanauma Bay, passersby waved and gave them the shaka sign, which means 'hang loose'.

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A surprised hiker managed to get a selfie with the President on the gruelling trail Oakroot/Instagram

Looking relaxed, the President, who was accompanied by his entourage of secret service agents, smiled and greeted fellow hikers with a handshake as they allowed him to pass them up the 1,048 wooden steps.

Many of the travelers even managed to take selfies with the President. "Selfie At the top of KOKO HEAD WITH PRESIDENT OBAMA!! ����(& his secret service agents lol) he was SO nice! MOST memorable time doing Koko! #kokohead #president #Obama #soawesome," wrote Ke-hau_wow on her Instagram.

"Okay, OBAMA, you pose for the cameras! Still can't believe I was so close! ������ #obama #kokohead #rikasphoto," Ke-hau_wow added.

President Obama
A hiker snaps a selfie with the president Ke-hau Kemioke/Instagram

"Climbing Koko Head Crater with President Obama. It was so exciting meeting him!! #POTUS #Hawaii," wrote Krissia_Nicole.

Another hiker posted a video of Obama on the trail. "Thanks for your service, Mr. President," the man says in the video posted to Facebook.

The President and The First Lady will spend two weeks with their daughters Malia and Sasha in Hawaii, which is the commander-in-chief's home state. The president has been having an active holiday, exercising in the gym at the Marine Corps Base Hawaii in Kaneohe. On Monday he had a round of golf at the exclusive Mid Pacific Country Club and spent time at his vacation home in Kailua. The first family dined at upscale Japanese restaurant Morimotos in Waikiki, after their day of hiking.

President Obama
The President takes a break during the hike at Koko Head dtmad3it/Instagram

The total cost of Obama's vacations since taking office in January 2009 is said to be in the region of $70.5million, according to new report, as it was revealed Obama has played around 250 golf games throughout his presidency.

On the way to Hawaii, Obama stopped in Southern California to meet with the relatives of the victims of the San Bernardino massacre.