Twitter demands phone verification, but I don't have a phone. I already verified my E-mail, what's going on?

Like the title says, I can't log in to my Twitter account. I did so yesterday, but today all I get is a screen telling me to verify through phone.

I don't have one, does that mean I can't use Twitter?? I'm also not in the US, so I can't use Google Voice to bypass this.

Can someone help?