Police investigating bomb threats to 6 schools around Washington, D.C.

Police in Washington, D.C. has said they are investigating bomb threats made to six schools around the US capital.

The schools, including Dunbar High School, are currently being evacuated, the Metropolitan Police Department tweeted on Wednesday afternoon.

The evacuations came a day after US second gentleman Doug Emhoff was escorted out of an event at Dunbar High School due to a bomb threat, Xinhua news agency reported.

More than a dozen historically black colleges and universities (HBCUs) around the US also received bomb threats in early days of this month dedicated to honouring achievements and struggles of African Americans throughout US history.

A law enforcement official has said the FBI has identified six persons of interest around the country, all juveniles, who are suspected of making the threats against the HBCUs.

The official added they appear to be "tech savvy," using sophisticated methods to try to disguise the source of the threats, which appear to have a racist motivation.