There was a message left for me from the 800 number.  It was to alert me of a possible credit card problem.  They left a call back number: 1-800-690-8056, but did suggest calling the number on the back of my card if I was suspicious. I had received this same call a week ago.

This wasn't a scam.  Citibank cancelled my card and sent me a new one.

Your advice is very sound.  The person answering was very unprofessional and wouldn't give me her ID number.  I asked to be transferred to her manager "Justin in Missouri".  He reverse looked up my accounts using my phone number and I would only confirm my first name, I asked him to give me the first letter of my last name before I would finish telling him any other information.   I was told my accounts may have been closed and new cards would be mailed out.  Apparently I was sufficiently upset that I was plied with a $25 credit for my troubles.  I asked that they wipe out my balance but that humor wasn't going to get me anywhere.

Received live voice recording message on our home phone answering machine asking to call this (1 800 690 8056) number. There was mentioning of "Fraud early warning" and that it was master card, NO mentioning of the bank. We called back and live lady picked up in a weird way, in an interruption of the "press this for that" automated message. She asked for card number, we did not provide it to her. Instead we called the number on the back of the Master Card we have which happen to be of the City Bank.

Although the original call seems to be legit, here is the advice for everyone getting this call. Ignore it and call customer service using the number on the back of your card. I don't know what City is thinking setting up the warning like that, but chances are very good that you do have fraudulent charges on your card!!! We did.

MOREOVER, I can tell you all with 100% certainty that City Bank has a leak of credit card numbers, NOT YOU!!!. Our card was NEVER, EVER USED in any transaction with any merchant. It was purposely ordered to be used exclusively to to use City's temporary card numbers feature for one time online orders. YET, the fraud charge we have, came to the main card number (printed on the actual card). Once again, this card is all new, not scratched by CC terminals, all shiny, not signed and sitting in the locked box at home.

Got a phone message from this place at work.  They identified themselves as the city fodder Lee Warning Department wanting to talk about your activity on your card.  We don't have a Citibank card.

There was a message left for me from "MARYLAND" 301-714-5301.  It was to alert me of a possible credit card problem.  They left a call back number of 1-800-690-8056.

Instead of using either of these numbers, I called customer service at my credit card company.  The call WAS LEGIT.  They cancelled my card and sent me a new one.

i got a voice mail today from 800-690-8056 indicating they are from Citigroup Credit card fraud alert and suspect risk of illegal activity on my Citibank credit card, and wanted me to call back.  i called the phonE # on the back of my card instead, and it turned out the call was legitimate. They informed me that my card was part of a group of credit card accounts obtained by a third party and there was increased risk of fraudulent activity on my card.  They said they would close the current credit card account and issue me a new card.
So it seems like the call from 800-690-8056 was legitimate.

Call from CITI, early fraud alert, I called to the number in the back of my card

Legit.

Just verified mins. ago by calling phone # on back of card instead.  I don't know why that number is not on their website right now.

This number was legit, but it makes sense always to be careful and just call the # on the back of the card.

In my case, a merchant I had used the card with had their data stolen, including my CC number. The merchant alerted Citi, which is why they alerted me to cancel the card and issue a new one.

legit.
Card may have been compromised, so they are cancelling and issuing a new card

Legit.

I called them back at that number.  It was in fact cit cards.  
I haven't used my card in a while and there was a charge on it today.  They just wanted to check with me first.

Citicard told me the number was not legit and that there were no problems with my account

this is LEGIT, i just called them and they said it was

Did not call this number but called the Citicard number in the back of my card. They said my account may have been compromised and a new card with a different account number is being sent to me, and to check my balance frequently.

Got a call from 301-714-5301 which advised me to call the 800 number on this page.  The lady at that number wanted my credit card #, which seemed like a very dumb way to handle "fraud" - so I just called the # on the back of my Citibank AmEx, and it did turn out to be legit call from their "fraud early warning" group.

Funny you should say that because I just got off the phone with Citi and their Fraud department told me calls from this number ARE FRAUDULENT. Good thing I did not give them ANY information.

I too got a call from 800-690-8056 stating that Citibank wanted to verify activity on the account.  When I called, they said that my card had been part of a group of numbers made available to a third party.  The card number, they said, was compromised and needed to be replaced.  They canceled my account and said they'd send another card by UPS.  It occurred to me to check to see if this call was legit. I called the number on the back of my card, and yes, the 800-690-8056 phone number "is" Citibank.  My card has been canceled.  A new one is on the way. So, all's good.

got the same call from the 800-690-8056 number and was of course skeptical since i had not handled the original call and someone at home told me i received a message.  i saw these messages so i decided to call citicards customer service instead and they were waiting for my return call... said my card has been compromised in some way and that i should destroy it and a new one would be sent in the mail.

if it had not been for the messages above, i would have worried much more and possibly not returned the call.

Got a notice in the mail from my credit card company fraud department asking me to call thi snumber about my account.  I called the customer service number from my statement instead but they said that this was a legitimate phone number and there was in fact a fraud alert.

Received a message on my voicemail to alert me of potential fraud on my Citibank credit card.  Asked me to call 1-800-690-8056.

I did the same as Don and called the regular customer service number on the back of my card.  This call was LEGIT.  They also cancelled my card and sent me a new one.

called my cell phone, I didn't answer.