Can my landlord still charge me for "damages" if he already returned my security deposit?

My landlord returned the security deposit within 30 days of the end of the lease (like he was supposed to according to law), but on top of having deducted money for normal wear and tear (e.g. touch up paint, bathroom cleaning fees, etc), he's now asking for more money for damage that we supposedly did to the house even after he'd already returned our deposits. Can we just ignore him? Sue him? Or do we still have to argue with him over every little thing he's accusing us of?