The U.S. Defense Department will increase COVID-19 restrictions at the Pentagon Reservation effective at 5 a.m. Thursday.

The move to Health Protection Condition Bravo Plus was announced Tuesday in response to an increase in COVID-19 cases in the region. The restrictions apply to the Pentagon, the Mark Center Campus and Raven Rock Mountain Complex.

"Protecting our workforce while still performing our national security mission remains the Secretary of Defense's number one priority during the COVID-19 pandemic," the Defense Department said in a statement.

"Supervisors will continue to provide maximum telework opportunities and flexible scheduling to optimize the workforce while defending our nation, taking care of our people, and ensuring success through teamwork," DoD said.

Masks and physical distancing of at least 6 feet will be required indoors throughout the Pentagon Reservation, with occupancy rates to remain less than 40%. The department will maintain maximum telework, and precautions to protect medically vulnerable personnel will be taken.

The restrictions also call for 10% to 20% of the workforce and 100% of visitors to be screened for COVID-19 upon entrance.

Public tours and the Pentagon National 9/11 Memorial will also be closed except for pre-approved activities, with gatherings limited to fewer than 25 people.

Since Aug. 2, daily new cases of COVID-19 within a 30-mile radius of the Pentagon have risen from a two-week average of 13.6 per 100,000 people to 19 per 100,000 people, according to a Defense Department memorandum, which noted a "disturbing trend of increased hospitalizations."

The threshold for enacting HPCON Bravo+ restrictions is 16-30 new cases per 100,000 people.

Secretary Lloyd Austin has called for all service members to be vaccinated. The U.S. Navy and Marine Corps issued memos giving all active duty and reserve service members until the end of the year to be vaccinated.

As of Sept. 1, 1.12 million service members and 310,669 civilians had fully vaccinated by DoD, according to the Pentagon's latest numbers.

The department has reported a total of 347,604 COVID-19 cases, 4,849 hospitalization and 436 deaths.

Last month, the Army announced that the 2021 Department of Defense Warrior Games would be canceled because of concerns about rising cases of COVID-19.