A few observations if I may. It is open ground --- that's been said and is obvious. The riflemen all appear to be
African-Americans. Only the two who appear to be holding R/T hand pieces and may be officers look to be White. The 'officers', if that's who they are, appear to be focused on something that is seemingly distant and possibly a target. It appears to be a small lightly equipped ground unit operating with armour, and apparently not too concerned about a potential anti-armour threat.

A possible conclusion is that it is an African American infantry unit engaged in a 'mopping-up' operation.