Never carry your US passport in a bag, suitcase or purse.

Foreign travelers are urged to carry their passports on their person at all times. However, it's far too easy for a criminal to snatch a purse, bag or suitcase and run.

I recommend: Never assume that you can outwit a professional thief.  You should simply avoid carrying it in a bag that can be snatched.  One option is to carry your passport in a pocket.  Try to choose clothing for your trip that has pockets with button-down flap enclosures.  Choose an inner pocket if possible.  Or, wear two shirts, carrying your passport in the inside shirt.  Another option is to carry your US passport in a money belt.  Tuck the money belt underneath your clothing, as close to your skin as you can.

Keep other identification separate from your US passport.

Despite your best precautions, it's possible that your passport may get stolen anyway.

I recommend: Carry your driver's license, Social Security card and other identification in a separate pocket or money belt from your passport.  That way, if your passport does get stolen, you won't lose all of your other important documents too.

Never leave your US passport unattended.

Protecting your US passport means keeping it secure at all times. Professional criminals prey on tourists and are adept at scouting hotels for potential victims.

I recommend: Don't leave your passport in a hotel room when you go out.  If you don't plan to carry it with you, leave it in your hotel's safety deposit box.  The charge for this service is usually fairly minimal.  It's well worth the cost when you consider the possible price you'll pay if your US passport gets stolen.

Always keep your US passport concealed.

Don't make it easy for would-be identity thieves to target you.

I recommend: Keep it tucked away and hidden in your pocket or money belt when carrying it on your person.  If you have to take it out to use it, be inconspicuous, and return it to its hiding place immediately.