Vandals defaced a campaign billboard for Donald Trump in Phoenix.

The billboard, located along the junction of Interstates 10 and 17, was vandalized with swastikas and is visible from the freeway.

The swastikas appear around the candidate's well-known "make America great again" slogan, but do not obscure it or his name.

The Phoenix police bias squad is investigating.

Trump is scheduled to speak in Prescott Valley, Arizona on Tuesday afternoon.

The billboard located along the junction of Interstates 10 and 17 was vandalized with swastikas. (Photo: 12 News)