Both Revised Standard Version and Good News Bible insert a paragraph break here, which we recommend.

When no less than nine thousand took refuge in two very strong towers well equipped to withstand a siege: At least 9,000 Idumean soldiers escaped the slaughter and found safety in two strong towers. Took refuge in may be rendered “managed to escape to.” Very strong and “easily defended” (Good News Bible) mean the same thing. If something is easily defended, it is strong. For towers see the comments on 1Macc 1.33. Towers is better than “forts” (Good News Bible). Well equipped to withstand a siege means that there were provisions for food and water in the towers that would allow the Idumean defenders to stay a long time, surrounded by Judas’ men.

Good News Bible renders this verse as a separate sentence, which is helpful.

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on 1-2 Maccabees. (UBS Helps for Translators). New York: UBS, 2011. For this and other handbooks for translators see here.