MINNEAPOLIS (AP) -- Police have arrested 18 demonstrators who shut down part of the light rail system in Minneapolis to protest federal immigration deportations.

Demonstrators sat on the light rail tracks near Minneapolis-St. Paul International Airport Tuesday morning, shutting down light rail service for over an hour. Metro Transit spokesman Howie Padilla says police arrested 18 people. Trains began running shortly after.

The protest is part of the Poor People's Campaign, a national group focusing on issues including poverty and racial inequity.

The demonstration follows efforts to toughen disruptive protests that block highways, public transit and airports in Minnesota. Gov. Mark Dayton vetoed the proposal.