After the National Zoo was evacuated Tuesday over a reported bomb threat, D.C. police said a “precautionary sweep” of the area turned up no “hazardous materials.”

Police gave the all-clear shortly before 1:45 p.m. Tuesday, more than two hours after the zoo was evacuated.

Police said the Smithsonian National Zoo in Northwest D.C. received the bomb threat at 10:42 a.m. Police got the call about the threat at 11:09 a.m., and visitors and staff were evacuated out of an abundance of caution.

During the sweep, roads around the zoo were closed.

A stretch of Connecticut Avenue Northwest directly in front of the zoo from Cathedral Avenue to about Devonshire Place was closed for the investigation.

The zoo said in a statement the zoo will remain closed Tuesday and reopen Wednesday.