The Walter Reed National Medical Center just outside of Washington has been given the all-clear by authorities after a false gunshot alarm was called in, the second one in the area in a week.

Authorities ordered staff to stay put in place as they swept the 20-story complex with sniffer dogs after reports of gunshots sparked a lockdown at the facility. After the investigation, it was reported that there were no signs of any shots fired at all, according to The Sun Daily.

The US Navy confirmed that the police found no evidence of gunshots or injuries.

“There is no evidence or any indication of a firearm being discharged,” Montgomery County Police spokesman Captain Paul Starks said.

A call was made to the police at 10:48am GMT by an individual within the complex. Police took the time to interview the person directly about what prompted them to make the call.

“They heard some noise that they thought could have been shots,” Starks said.

Once they received the call, police quickly responded in fear it could actually be an active shooter at the hospital.

After the call was made and the police were on the way, a “code white” was declared at the facility which meant a lockdown of 7,000 employees. The alert triggered staff members to immediately take cover where they were, which meant some employees hiding in bathrooms and under desks.

The intense reaction to the call was warranted by a weekend of heightened security across the US during the Independence Day Holiday. Monday’s event was also following a similar false alarm of gunfire also triggering a lockdown at the Washington Navy Yard where in 2013, 12 people were killed by a single gunman.

Walter Reed National Military Medical Center is the biggest military hospital complex in the world, located in Bethesda, Maryland spanning over 243 acres.