Facebook security check

Hello,

When I login to facebook it sends me to a security check page and asks me to enter a mobile phone number. When I click on the button "Enter mobile phone number" is says that "Your current session has expired. Please login again to continue." So it won't let me enter a mobile number without being logged in and it won't let me login without entering a mobile number and passing the security check. I am using the Chrome browser but have tried IE as well.

David