The mayor of Bristol says he has received letters telling him to "get out of the country" since a statue of a slave trader was toppled in the city.
Marvin Rees has been sent "several offensive letters", a racist book and a "black doll badge" in the past week.
He previously described the statue of Edward Colston as an "affront to me and people like me".
Avon and Somerset Police said it was investigating a report of racially aggravated comments being made.
Mr Rees became the first mayor of black African heritage to be elected by constituents in the UK in 2016.
He said the issue of race had "always been there waiting to be agitated" and the fall of the Colston statue had brought it to the fore.
The bronze sculpture's removal, and protests sparked by the death of George Floyd in the US, had exposed "underlying weaknesses in our society", he said.
"I think people have been living in a dream world if they thought over the passage of time somehow we had got to a world where we were living Martin Luther King's dream and there was racial peace."
Mr Rees said he had been subject to ongoing correspondence "questioning [his] place in society" but there had been an increase.
"This is linked to a bigger, national campaign to agitate along race lines and far-right activism.
"I've had letters overtly telling me if I don't like the country, get out," he said.
Mr Rees said it was important not to let hostility distract from the "underlying structural inequality of people with black and brown skin having a lower life expectancy, being disproportionately likely to end up with lower education outcomes and end up in mental health institutions or prisons."
Avon and Somerset Constabulary Ch Insp Paul Wigginton said: "We've received a report regarding racially aggravated comments being made. An active ongoing investigation into the matter is underway."