What should I do if he won't stop?

I have been talking to a man via a dating website, and the conversation is usually really nice, but lately when we talk he keeps making remarks about things he would like to do such as massage me, kiss me, etc. I have expressed to him that it makes me uncomfortable and it stops, but then two or three days later he does it again. He hasn't made any effort to make contact in person, just by email. Am I being too cautious by telling him how I feel about it instead of letting him talk? I find it disrespectful that he would continue to do it. I know I should probably ignore any further messages, but like I said, we do have good conversations most of the time.