Despite all the growth in technology, telephone scams still remain the top threat to consumers, and in particular by using a phone scam to engage in identity theft. The goal of the scammer is to catch you off-guard—sometimes calling in the middle of the night or on your cell phone in the middle of the work day—and get the information they need in minutes to steal your money or your identity.

Imagine this: You get a call from someone who identifies themselves as a border official telling you that your Social Security number was being used to try and obtain a passport. The “official” says all the right things: You aren’t being investigated, but he needs your help to nab the person who is.

Is the call legitimate? No. The real U.S. Customs and Border Protection confirms that every year, thousands of people—seniors included—lose money via telephone scams involving criminals posing as customs officials.

Here are some red flags that can help you to decide whether a caller is legitimate or not, and to protect yourself from being the victim of a telephone scam.

• A legitimate issue with government documentation would not come via telephone. Institutions like the U.S. Customs and Border Protection wouldn’t telephone you to advise of an issue with your Social Security number or that you were the victim of identity theft. It’s not how they operate. Any calls that come in of that nature should be disconnected immediately.
• The scammer is putting pressure on you through threatsAt no time would a legitimate agency threaten you with possible intervention from law enforcement or prosecution via a telephone call, in order to secure your cooperation.
• There is an extreme time pressure for you to respond to their requests for information. For example, if the caller is telling you to provide what they need within minutes or face prosecution, be wary. This is a tactic meant to frighten you beyond the threats themselves, to get the information they want quickly, before you have to time to consider the legitimacy of the request. Another red flag that is similar to this one is when you are told you have X time to cooperate, but that time window shifts as the call continues.
• The scammer is advising you not to communicate with others. Whether it’s the possibility of your telling your spouse about the call, your work colleague or contacting a law enforcement agency, the scammers want to avoid this at all costs and might tell you not to share the discussion, for fear of compromising their efforts to “catch the bad guys.” However, law enforcement of any type isn’t in the business of bringing civilians in on the action.
• The caller’s phone number doesn’t correspond correctly to who claims to be calling. Caller ID is not a safe way to identify a caller, as fake numbers can be displayed. If you see an area code or toll-free code that just doesn’t make sense, look it up. Odds are you’re not the first to receive a call from that number and can find others who have reported it as a scam.
• The scammer wants you to use gift cards to transfer money to them. In the throes of a call in which you are being told there is a time limit to help and threats of prosecution are coming fast and furious, causing you stress, you could miss this flag.

Protect yourself by being wary of calls that come in on your cell phone, in particular. If you feel that a call might be legitimate, ask for the person’s name, hang up and call the organization in question.

Justin Lavelle, who wrote this story, is chief communications officer beenverified.com, a source of anti-scam services.