DES MOINES, Iowa (AP) -- Iowa House Republicans have passed a bill that would require local governments to install metal detectors or armed guards at entrances to government-controlled buildings that prohibit firearms.

The bill pushed by gun rights advocate Rep. Steven Holt passed Thursday with only Republican support.

Holt argued that gun-free zones prohibit him and other legal gun carriers from protecting their families from shooters.

Cities and counties opposed the bill because of the cost of hiring guards or installing equipment at city halls, libraries, courthouses and other public buildings where guns aren't allowed.

The bill advances to the Senate.