Ferguson - Two FBI officers were shot and wounded at a house in north St Louis County early on Wednesday, though it was not immediately clear if the incident was linked to racially-charged unrest in and around nearby Ferguson, media reported.
The agents were responding to a situation involving a person barricaded inside a house and suffered non-life threatening injuries, local broadcaster KSDK said on its website. The FBI did not immediately respond to requests for comment.
About 2 000 National Guard troops dispatched to the St Louis area helped police stave off a second night of rioting and arson after a grand jury declined to indict a white policeman in the fatal shooting of an unarmed black teenager, as sympathy protests spread to several US cities.