The federal government's jurisdiction over immigration law has consistently been upheld by the U.S. Supreme Court, which has overruled attempts by state legislatures to single out immigrants. Additionally, the Supremacy Clause of the U.S. Constitution is generally interpreted to mean that federal laws trump state laws, except for certain matters constitutionally left to the states.
The open question is to what (legal) extent the city could and should proactively resist or cooperate with Federal initiatives. 
If the Feds want to hold/deport an undocumented immigrant, no city declaration can legally stop it. (As much as I might wish it to be otherwise). Individuals can (and maybe should!) choose to resist, but beyond working within the rule of law allowed within the Supremacy Clause, what are you asking for? Kim Davis was within her rights as an individual to refuse (and face punishment for refusing) to perform marriages-- but our gay brothers and sisters can still marry. (Yay for that!)