Dep. Communications Director, Chris Hernandez, said the threat was called in to police and not an emergency line.
"That threat indicated that a bomb had been placed inside City Hall around 2:30 yesterday. Clearly, nothing has happened with that, so far. But, clearly, as a precaution, our security staff decided to evacuate the building," he said.
According to KMBC, a suspicious package was found near the fountain outside City Hall, but it was destroyed.
Police are searching the building floor by floor before allowing anyone to return to work.