CHICAGO (AP) — A sweeping expansion of deportation powers unveiled this week by the Trump administration has sent chills through immigrant communities and prompted some lawyers to advise migrants to gather up as much documentation as possible — pay stubs, apartment leases or even gym key tags — to prove they've been in the U.S.

But the uncertainty about how the policy might play out has created confusion and made it harder to give clear guidance to immigrants. Attorneys and immigrant rights groups gave conflicting advice about whether to carry these documents.

The new rules will allow immigrat...