The U.S. Postal Service is bracing for Joe Biden’s inauguration on Jan. 20 by temporarily removing some mailboxes in a number of major U.S. cities.

Additionally, USPS will delay mail collection at some mailboxes. “It's part of our normal procedures to keep our employees and customers safe during times of protest or when large crowds are gathered near postal facilities, on postal routes, or by mailboxes,” Postal Service spokesman David Partenheimer told CNN.

The security measures have been implemented to guarantee protection of postal property, employees, and the public, according to press releases that Postal Service jurisdictions sent out in at least 17 states and Washington D.C.

In D.C., USPS will either temporarily remove or lock mailboxes, and notices will be places on individual boxes pointing to the dates they will be unavailable for use. At least 14 post offices in D.C. will be briefly closed on Inauguration Day.

The Postal Service took similar steps for Trump’s inauguration in 2017, removing some mailboxes in the nation’s capital.

Extending the security measures to other cities rested on the Postal Service’s knowledge of “planned protests or other situations involving large crowds” in main cities and areas, Partenheimer said. The U.S. is preparing for another day of unrest on Jan. 20, with the FBI receiving information implying that “armed protests” are being set in motion at all 50 state capitals and in D.C.