The attack, which left at least seven dead and 25 wounded, has been claimed by the al-Shabab terror group and may have come as retaliation for Kenyan troops, who along with other forces brought together by the African Union, have been fighting the terrorist insurgency in Somalia.
Meanwhile, the US has kept secretive forces strewn across Africa. In 2017, a US Navy SEAL was killed in a battle fighting alongside Somali forces against al-Shabab in Mogadishu.
In March 2018, an ambush by militants in Niger claimed the lives of four service members.
The Pentagon has been reluctant to provide details on how exactly it supports different African nations in combating terrorist insurgencies, usually saying it's "advising and assisting" unnamed countries.
But even in Kenya, one of Africa's more stable countries, the US has a small presence at Camp Simba, where they reportedly train naval special forces. Kenya, like its neighbor, Somalia, has trouble with pirates and has seen some US Navy SEAL presence over the years.
In the video of the Nairobi terror attack, a white man wearing a US military-style backpack with a patch that's used by US Navy SEAL Team 3 can be seen rescuing civilians and then returning to the scene of the fighting in a state of alertness.
The man in question wears civilian clothes and covers his face, a style seen worn by US special forces elsewhere.
Business Insider contacted three spokespeople for US Africa Command, and none of them denied the possibility that the man in question was a US Navy SEAL.
The attack is considered over, Kenyan authorities told Reuters.
Watch the video below: