INDIANAPOLIS (AP) – More than 600 people, including lawmakers and best-selling author John Green, gathered at Indianapolis International Airport to protest President Donald Trump’s immigration restrictions.

The Indianapolis Star reports that what began as a small group grew to hundreds Sunday, as the Indianapolis Airport Authority roped off areas and increased security for protesters. Officials declined comment.

Cheryl Faux, one the Indianapolis event’s organizers, says the protest “gives a message to the Muslim community that we stand behind them.”

The demonstration was one of many at airports around the country since Trump signed an executive order banning travelers from seven predominantly Muslim countries.