D.C. Mayor Muriel Bowser responded to the rejection in a statement on Twitter, saying, “We will move forward with our programming to ensure that when people come through D.C. on their way to their final destination, we have a humane environment for them .” Bowser had originally sought support from the D.C. National Guard in late July, when she said the city had reached a “tipping point” with the number of immigrants. The governors of Texas and Arizona began moving migrants from the southern border to the capital starting in April in protest of President Joe Biden’s immigration policy. The Pentagon rejected the first request in early August, saying it would harm the readiness of the D.C. National Guard and that the city had received a grant through FEMA’s Emergency Food and Shelter Program. But a week after that denial, Bowser resubmitted her request for National Guard support, seeking to address some of the concerns raised by the Pentagon. Bowser said the request was for a 90-day period rather than an open-ended request and would be limited to logistical support for sites such as “facilities management, feeding, sanitation and ground support.” The mayor reiterated the need for a government facility like the DC Armory to be used as a “rest center” where immigrants can stay until they can move on. Her letter said the secretary “failed to demonstrate that he understands the urgent staffing and logistical challenges that have led me to make this serious request of our National Guard resources.” The D.C. National Guard, Bowser said, had “unique resources” to provide logistical support to the city. Instead of approving the request, the Pentagon reiterated its previous stance and explained in more detail the reasons for rejecting it. The Pentagon said the use of the D.C. National Guard would affect the unit’s readiness and that the D.C. Armory was not an appropriate place to house immigrants even temporarily, as it is not air-conditioned and would have to undergo “substantial rehabilitation for a number of issues,” according to the copy of the letter. The Ministry of Defense also pointed to civil services and NGOs that help with migrants. On Monday, the mayor said D.C. would continue to work with other federal agencies and nongovernmental organizations as part of her plan to deal with incoming immigrants and reiterated her call for D.C. to receive statehood, which would give it the authority to call out the National Guard without Pentagon approval. This story has been updated with additional details. CNN’s Aaron Pellish contributed to this report.