Originally Published: 12 AUG 22 10:32 ET

By Priscilla Alvarez and Barbara Starr, CNN

(CNN) -- Washington, DC, Mayor Muriel Bowser renewed her request for the National Guard to assist with the ongoing arrival of migrant buses arriving from Texas and Arizona.

"We need help from our federal partners as we seek to stabilize and manage our operating environment in this critical moment," Bowser said in a tweet on Thursday.

In a statement, a Defense Department spokesperson confirmed that the department had received the request.

"The Secretary takes this request for assistance very seriously. He and his team are working through the details, and will respond to the mayor's office as soon as a decision has been reached," the spokesperson said.

The Pentagon declined Bowser's previous request last week.

Defense Secretary Lloyd Austin rejected it because the Department of Defense has "determined providing this support would negatively impact the readiness of the DCNG and have negative effects on the organization and members," a defense official said.

According to the office of Texas Republican Gov. Greg Abbott, more than 6,500 migrants have arrived in Washington from Texas on more than 160 buses.

Bowser told reporters last week that she wants to continue to work with the Pentagon to ensure political considerations "are not a part of their decision."

The Democrat alluded to the use of the National Guard during the January 6, 2021, insurrection at the US Capitol: "Having the experience where the use of the DC National Guard was politicized, that puts the District in unsafe territory," she said last week.

"We want to continue to work with the Department of Defense so that they understand our operational needs, and to assure that any political considerations are not a part of their decision," she added.

The city has facilitated the help of the Federal Emergency Management Agency with a $1 million grant, the mayor said at a news conference earlier this month.