DENVER -- New security barriers have been put up in front of Denver's City and County building amid growing security concerns at the building.
The barriers are giant concrete blocks that have been placed on the plaza on the east side of the building, blocking vehicle access to the front doors.
The move comes after recent security scares at the building.
On Feb. 27, Denver police swarmed the building after a caller made a "credible threat" against the mayor. The building was searched for several hours but no suspect or weapon were found.
Before that, someone drove a car onto the plaza and right up to the front doors of the building.
And in January, barriers were placed on Bannock Street, closing the street - parking was also banned in front of the building.
With the concrete barriers now in place, cars are once again being allowed to park on the street.
Denver safety officials say threats against public buildings and officials have increased around the country.
Authorities stress that "if you see something, say something."