PHOENIX, Arizona - Protesters demonstrating against Donald Trump blocked the streets outside Trump's Arizona rally Saturday, making good on earlier promises to disrupt the GOP front-runner during his visit to the border state.

The activists, carrying signs that declared "Dump Trump" and "United Against Hate," shut down a main Arizona highway leading to the city of Fountain Hills, where Trump is holding a campaign event Saturday afternoon.

Protesters in cars and on foot encountered Maricopa County police during the demonstrations. Local media reported that some activists chained themselves to their cars in order to delay the towing of vehicles.

Sheriff Joe Arpaio, the controversial tough-on-immigration head of the Maricopa police who has pledged to provide security for the Trump event, said Saturday that his officers were working on the protests.

Arpaio, who has given Trump his endorsement, took the stage before the billionaire businessman at the rally. He announced that at least three people had been arrested from the protests.

Trump, who has made erecting a border wall a cornerstone of his presidential campaign, has drawn increasing fire over his contentious rhetoric on illegal immigration during the past month.