But in early July, the post was relocated to a trailer on the sidewalk, more than 50 floors below, a distance that some security experts worry could hamper the agency that protects the president's home and family.
The command post appears unlikely to move anytime soon back inside Trump Tower, where the president and his family have rarely gone since moving to the White House.
On Thursday, a spokeswoman for the Trump Organization said the government should seek space in another location.
"After much consideration, it was mutually determined that it would be more cost effective and logistically practical for the Secret Service to lease space elsewhere," spokeswoman Amanda Miller wrote in an email to The Washington Post.
The details of the dispute between the Trump Organization and the Secret Service were not clear Thursday. Two people familiar with the discussions said the sticking points included the price and other conditions of the lease.
On Thursday, there appeared to be a difference of opinion over whether negotiations for a Trump Tower space were still going on.
Despite the Trump Organization's statement to The Post on Thursday saying the agency should look elsewhere, Secret Service officials said the agency is still hoping for space in Trump Tower.
The agency is working "to obtain permanent work space in an appropriate location," said Catherine Milhoan, a Secret Service spokeswoman.
Milhoan added, "Throughout this process, there has been no impact to the security plan developed by the Secret Service."
A spokeswoman for the General Services Administration, which handles government leasing, declined to comment because the search for a command-post space is still active.
"The space is still in the process of being obtained and a final decision has not been made," spokeswoman Pamela Dixon wrote in an e-mail.
That move has provided a new illustration of the unusual nature of Trump's tenure, in which the president has retained ownership of a real estate and branding company.
In this case, Trump's government sought to be a customer of Trump's business. To protect him, the agency needed space in the pricey tower where he lives. But the two sides couldn't agree. The Trump Organization was willing to accept a situation where the agents moved out and the space was available for others.
Trump has not visited Trump Tower since he was inaugurated. His wife, first lady Melania Trump, and their son Barron lived there for several months, but relocated to Washington in early June.
Still, the Secret Service treats Trump Tower as the president's permanent home, and has a full-time detail to protect it.
Experts said the Secret Service will have a presence inside the building if Trump or his family members visit, as their personal security details would remain in close proximity.
A Secret Service official said Thursday that the agency could compensate at other times by stationing more agents at standing posts in various locations throughout the building.
But experts said that the lack of a nearby command post could make the situation less safe in an emergency.
"It's a security deficiency that has to be resolved," said a former Secret Service official who spoke on the condition of anonymity because of the sensitivity of the subject. "It's like having the quarterback of the football game actually being located in a different stadium than where the game is being played."
The Secret Service command post acts as a nerve center for a broader team of agents, both at a president's private home and when the president travels. The command post is usually located on the same floor as the suite or room where the president is sleeping, or one floor below.
At Trump Tower, the command post had operated temporarily for months in the offices of the Trump Organization, one floor below the president's residence.
Now, with the post on the street below, security experts worry that radio transmissions could break up because of the distance and multiple walls between agents on the scene and commanders in the trailer.
The U.S. military has separately agreed to lease space in Trump Tower for $130,000 a month, according to a lease first reported last month by the Wall Street Journal. That space will be for the White House Military Office, which provides services including communications and the handling of the "football" that the president would use to launch a nuclear attack, the Journal reported.
The Journal reported that the military was paying more for this unit than other renters had paid for similar units in the building.
In that case, however, the unit was not leased directly from Trump — but rather from Joel Anderson, a businessman who owns the space. In an interview Thursday, Anderson said that the government didn't really try to negotiate a lower price.
"It was a standard lease negotiation, like any other, and had all of the same parts. The only thing that made it difficult it is they're bureaucratic, and it takes them forever to do anything," Anderson said. "They're not bad to deal with, they're just slow."
The lease agreement in that case — which runs to 149 pages — illustrates the extra conditions that may come from leasing space to the government. Its provisions ask that the owner of the space follow energy-efficiency guidelines, submit reports on its compliance with fair-hiring practices, and post signs with a hotline for reporting contract fraud.
Julie Tate, Drew Harwell and Amy Brittain contributed to this report.