Breen Barrier

The Breen Barrier was a military conflict, an interstellar war initiated by the Breen Confederacy against the United Federation of Planets to prevent Starfleet from extraditing a Breen prisoner to the Romulan Star Empire. ( mission: "Breen Barrier}})

Prelude
After conflicts and the fallout from events in the Trexelian Expanse, the Federation and Romulan Star Empire improved their relations with diplomatic talks around stardate 73XX.6. ( mission: "Breen Barrier}})

Conflict
The conflict began when the Breen instigated a blockade, to prevent Starfleet battle groups from reaching Romulan space. Starfleet responded by countering the Breen fleets in Federation and Breen space with ships from Battle Group 1, Battle Group 2, Battle Group 3 and Battle Group 4. The BGs carried diplomats into the Breen heartland and defeated the attacking and defending Breen Militia fleets. During this war, the Breen fielded prototypes of the new bird-of-prey, based on the Romulan  warbird. ( mission: "Breen Barrier}})

Result
The conflict ended with a Federation victory. Starfleet captured the Breen tier 4 warship BRE, adding it to Battle Group 4 before it returned to the Trexelian Expanse. ( mission: "Breen Barrier}})