Hours after a bomb threat at the Department of Health and Human Services headquarters on Wednesday triggered evacuations at government buildings near the U.S. Capitol, police issued an “all clear,” allowing people to return to the buildings.

The incident unfolded Wednesday morning after there was a “bomb threat received” at the Hubert H. Humphrey Building in the 200 block of Independence Avenue SW, HHS spokeswoman Sarah Lovenheim said in a statement. The building was evacuated “out of an abundance of caution,” but there was “no reported incident,” she said.

Just before noon, emails went out to Capitol Hill staffers informing them that the O’Neill House Office Building and U.S. Botanic Garden also had been evacuated. Some streets along Independence Avenue SW and C Street SW were closed.

U.S. Capitol Police gave the “all clear” for the O’Neill House Office Building about 1:30 p.m., and reentry to the building was authorized there at that time; reentry at the HHS building was authorized at 2:30 p.m. All roads that were closed in response to the incident have been reopened, Capitol Police said.

Cheryl R. Campbell, assistant secretary for administration at the HHS, wrote in an email to staffers that security sweeps were conducted at the Mary E. Switzer, Thomas P. O’Neill Jr. and Wilbur J. Cohen federal buildings. Officials later said all buildings were cleared.

Capitol Police and D.C. police said they assisted the Federal Protective Service in “investigating the suspicious package” at the HHS building. D.C. police said their explosive ordinance disposal unit went to the scene.

HHS did not respond to specific questions about the bomb threat, including whether any motive was alleged.

In a statement Wednesday evening, a spokesperson for the Department of Homeland Security said “no direct threats were detected.” The statement said the Federal Protective Service “will continue to investigate the origin of this threat.”

HHS has faced intense scrutiny during the coronavirus pandemic, with some politicians and prominent conservatives berating senior HHS officials and amplifying threats against them. Former White House chief strategist Stephen K. Bannon last year called for Anthony S. Fauci, the government’s top infectious-diseases expert, to be beheaded.

Republican lawmakers this month also have circulated documents linking HHS to animal experimentation and suggesting that federal funds helped virologists in Wuhan, China, develop more dangerous forms of coronaviruses, assertions that have stirred anger in conservative media circles.

Peter Hermann contributed to this report.