WASHINGTON — Nooses have appeared recently around the nation’s capital — including the Smithsonian’s new African-American history museum — in a rash of incidents that experts say shows the growing use of hate symbols in the United States to try to intimidate minorities.

‘‘We’ve seen a spike in the use of symbols of hate lately, and the noose is one more example,’’ said Denison University professor Jack Shuler, who has studied lynching and noose imagery in the United States.

Two nooses were found at Smithsonian museums in the past week, one outside the Hirshhorn Museum last Friday and one inside the Smithsonian National Museum of African American History and Cultureon Wednesday.

Bananas tied to nooses were discovered at American University in Washington last month, while a noose was found at the nearby University of Maryland and a suburban middle school in Crofton, Md.

Two 19-year-old white men were arrested and charged with hate crimes for allegedly hanging the noose at the Crofton school. No arrests have been made in the other cases.

The Southern Poverty Law Center, which tracks bigotry, said it has seen an increase in hate incidents in the U.S. since the election of President Trump. Between Election Day and Feb. 1, the SPLC said, it collected information on about 1,800 hate-related episodes from almost every state.

‘‘In the past, it would be a couple hundred at most, and that would be high,’’ said Heidi Beirich, director of the Intelligence Project at the Southern Poverty Law Center.

Associated Press