(The Hill) — Six Washington, D.C., schools were evacuated on Wednesday while authorities responded to multiple bomb threats but ultimately found no explosives, the city’s Metropolitan Police Department said Wednesday.

In a tweet around 1:25 p.m., police said authorities were responding to bomb threats at six schools belonging to DC Public Schools and DC Charter Schools. The police said the “schools are currently being evacuated” and “investigations are ongoing.”

The Metropolitan Police Department said at 2:45 p.m. that “each of the schools have been cleared with no hazardous material found.”

The schools being investigated were Dunbar High School, Theodore Roosevelt High School, Ron Brown High School, KIPP DC College Preparatory, IDEA Public Charter School and Seed Public Charter School.

“DC Public Schools has been made aware of security threats at Dunbar, Roosevelt and Ron Brown High Schools this afternoon. All students and staff were safely evacuated in accordance with DCPS protocols. DC Public Schools values the safety of all our students, staff, and visitors and will continue to offer support to our school communities while the MPD investigations are ongoing,” DC Public School press secretary Enrique Gutierrez told local station ABC7.

Chancellor Lewis Ferebee said on Twitter that in the past 24 hours, DC Public Schools had received bomb threats at “three of our high schools,” and referred to them as “troublesome incidents that we take very seriously.”

The multiple bomb threats come just a day after second gentleman Doug Emhoff was escorted out of a Black History Month event at a DCPS high school after the school reported a security threat.

A spokesperson for DC Public Schools told a reporter at the scene on Tuesday that there was a bomb threat reported at the school. Teachers and students in the building were also evacuated and no explosives were found.