Update to this story about British woman and this about American participants.

Via Sky News:

A British woman and “two or three Americans” are among the militants who took part in an attack on a shopping centre in Nairobi.

Kenya’s Foreign Minister Amina Mohamed has confirmed that al Shabaab fighters were responsible for the attack, adding that the militants included Americans and a Briton.

In an interview with the PBS Newshour programme, Ms Mohamed said: “Both the victims and the perpetrators you know came from Kenya, the United Kingdom and the United States.

“From the information that we have, (there are) two or three Americans, and I think so far I have heard of one Brit.”

Asked about the British woman, Ms Mohamed added: “A woman, woman, and I think she has done this many times before