A British SAS trooper piled into the Kenya terror siege – killing militants and saving lives, it was confirmed today.

The “long-serving” member of the SAS – motto Who Dares Wins – was on a mission to train and mentor Kenyan Special Forces when four terrorists attacked a hotel complex.

After one detonated a suicide belt the remaining three went on a rampage, leaving 14 dead, including one American.

An unidentified member of Britain's SAS discusses with Kenyan security forces before entering to clear a building at a hotel complex in Nairobi, Kenya Tuesday, Jan. 15, 2019.  (AP Photo/Ben Curtis)

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Amid the carnage – orchestrated by terror group al-Shabab – a lone SAS soldier got tooled up and went in after a request for help from Kenyan security forces, sources said.

Incredible images showed the operator in jeans, sneakers and body armor storming through doors and aiding injured, his face covered by a balaclava.

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He was pictured operating at the hotel alone. But he was joined in the mission by US Navy Seals, sources said.

An insider told The Sun: "UK Special Forces always run towards the sound of gunfire. He was there training and mentoring Kenyan forces when the shout went up, so they went in.

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Incredible images showed the operator in jeans, sneakers and body armor storming through doors and aiding injured, his face covered by a balaclava. (REUTERS)

"During the operation he fired off some rounds – it’s a safe bet he hit his target – the SAS don’t miss.

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"He is a long-serving member of the Regiment, there is no doubt his actions saved lives."

This story originally appeared in The Sun. For more from The Sun, click here.