In a business meeting, there are two situations in which people often run into difficulties. These are when you want to interrupt someone who is speaking, for whatever reason, and when you are asked to comment on something you don't want to comment on (either because you don't have enough information to give your opinion, or because you
don't wish to speak for your own reasons).

If you need to interrupt, here are some phrases you may find helpful (and remember to consider your timing when using them, too!):

Do you mind if I interrupt? I must just say that...
Just a minute...
May I add something here?
May I interrupt here?
May I just say something on that point?
Or use that wonderful word, "sorry":
Sorry, I must just point out that...
Sorry, could I interrupt a moment?
Sorry, but I must say that...
Sorry, could I just say something?
"Sorry" makes an interruption of a meeting a little more polite.

But to avoid making a comment on an issue, "I'm afraid" works better:

I'm afraid I can't comment at the moment... (then give a reason why: I need to check on the latest information / I'd like a little more clarification on this issue from Ms. Leung, etc.)
I'm afraid I'm not able to say. (+ reason)
I'm afraid I'd rather not go into detail here, if you don't mind.
Using "I'm afraid" is better here than "I'm sorry", as "I'm sorry" puts the blame on you and indicates that it is your fault, while "I'm afraid" just indicates that you may feel some regret, but it is not necessarily your fault.

Other options include:

Do you mind if we talk about that later?
Can we put it off until later?
I don't think there's any point in going into detail at this stage.
That information isn't available yet, but we could talk about it... (give date or time)
I'd rather not say. (simple and direct, but honest)