The executive order issued by U.S. President Donald Trump to rename the Department of Defense to "Department of War" could cost up to $2 billion.

This was reported by NBC News citing six informed sources.

The report indicates that renaming the Pentagon will require the replacement of thousands of signs, posters, forms, and badges, as well as other items at military facilities worldwide.

According to four congressional officials and another NBC News source, the new forms and signs for the "Department of War" could cost around $1 billion alone.

The overall costs will be significantly influenced by the need to alter code for all internal and external Pentagon websites, as well as other software on classified and unclassified systems, the NBC News sources added.

Pentagon spokesperson Sean Parnell responded to inquiries by saying that a final cost estimate for the name change is not available due to the "government shutdown caused by the Democrats".

"This change, which pays homage to our proud legacy, is necessary as it reflects the core mission of the Department: to win wars", he added.

In September, President Donald Trump signed an executive order granting the U.S. Department of Defense an additional title – "Department of War".

From now on, the U.S. Secretary of Defense is authorized to use the additional title – Secretary of War – in official correspondence, public communications, ceremonial events, and non-statutory executive documents.