The base on Regulak IV destroyed
Regulak IV was the fourth planet in its star system. It was located in Cardassian space, and was the site of a base of the Cardassian Liberation Front.
The base was one of eighteen destroyed by Dominion forces in late 2375. (DS9: "The Dogs of War")
According to the script, Regulak was pronounced as "REH-gu-lack".
The same script also noted that footage that included this base was described as "stock opticals of Jem'Hadar and Cardassian ships firing – intercut with stock shots of asteroids, planets, bases, etc. being destroyed." In particular, footage of this base was reused from the Chin'tokan moon that previously appeared in "Tears of the Prophets".
According to Star Trek: Star Charts (p. 46) and Stellar Cartography: The Starfleet Reference Library ("Stellar Cartography", pp. 18-19; "Federation Historical Highlights, 2161-2385"), the Regulak system was located in the Alpha Quadrant. The primary was a M-class star. According to a map of the Cardassian Union – prepared by an anonymous astrography clerk, from the Cardassian Central Archives, in 2364 – Regulak was identified as a Cardassian system.