|Siege of Sector 21607|
|Part of Dominion War|
|Location:||Sector 21607, near the Tong Beak Nebula|
|Battle of Torros III||Battle of Tyra|
The Siege of Sector 21607 was one of the earliest battles of the Dominion War just over month after the Second Battle of Deep Space 9 and the Battle of Torros III. The battle fought Starfleet's Fifth and Seventh Fleets against a large Dominion armada.
Following the mining of the Bajoran wormhole and the attack on the Torros III shipyards, the Dominion was highly vulnerable. The Founders began preparing for the possibility of going without reinforcements from the Gamma Quadrant for several months. To that end, Weyoun set a plan in motion to make up for the losses suffered at Torros III.
Former Bajoran Resistance and Maquis fighter Hasin Arnit sent a message to Starfleet claiming to have stumbled across a Jem'Hadar breeding facility somewhere in Sector 21607. He had believed the Federation to be just as much to blame for the deaths of thousands of his colleagues and wished the same casualties to be inflicted on it. Through Hasin's sabotage, the crew of the USS Lambda Paz believed they had indeed found a Jem'Hadar breeding facility on a planetoid in the Tong Beak Nebula.
At a debriefing at Starbase 375, Lamba Paz captain Limis Vircona persuaded Admiral Ross and fleet commanders to go through with an offensive, stating that even if the Federation suffered heavy losses, that would pale in comparison to setting the Dominion back even further.
Later investigation revealed that no breeding facility existed in the nebula. Before the two fleets could fall back, they were confronted by an armada of 1,623 Dominion warships. The larger fleet was bent on destroying every ship in the Fifth and Seventh Fleets. That goal would have been achieved if not for Hasin's act of contrition. Having escaped in a shuttle earlier, he laid in a collision course for the Dominion flagship, allowing a sizable number of Federation and Klingon starships to escape, including the Lambda Paz commanded by his former spouse Limis Vircona. (Star Trek: Lambda Paz "Revenge a Dish Best Served Cold")