How do I use biological weapons in Next War?

[Flamegrape]

I have a missile cruiser. It's loaded up with biological warfare missiles. I'm at war. An enemy city is in range. What do I do? Air strike doesn't work. I press the air strike button, put the cursor over the enemy city, click the mouse button, and nothing happens. The missile isn't expended, nothing happens. It's as if it's not allowed.

How am I supposed to use this weapon?