The Multi-National United Security Force is the main source of security in District 9.
The MNU operates its own private security force and paramilitary contractors, whom strength appears to match any nation's own armed forces. The security forces are split into two groups: , and the First Reaction Battallion.
The primary , who are armed with Vektor CR-21 bullpup rifles. They man checkpoints and are the primary source of security in District 9 and the MNU Headquarter Building. Little is known about the primary , other then they escorted MNU Agents during the District 9 eviction and relocation process.
First Reaction Battallion
The more First Reaction Battallion are armed with state of the art weapons like the FN SCAR and Scorpion class body armor with biowarfare protection, while their ground vehicles apear to be mostly belong to MRAP projects. These units work in groups and are meant to deal with the aliens through lethal force. They are mostly seen deployed in teams of two from small and quick helicopters, that drop them into hot spots where they subdue the hostile aliens they come across.
- According to Neil Blomkamp in his commentary on the DVD of the movie, the First Reaction Battallion was inspired by Executive Outcomes, a defunct South African private military company that was very active in the African continent during the 1990's. Many of its former members (including its founder Eeben Barlow) formed the new PMC STTEP .