The Biden administration returned to the Supreme Court on Thursday asking the justices to once again allow the government to regulate so-called ghost guns, arguing that a lower court had essentially revoked an order the justices issued just two months ago.

Ghost guns are kits that a user can buy online to assemble a fully functional firearm. They have no serial numbers, do not require background checks and provide no transfer records for easy traceability. Critics say they are attractive to people who are legally prohibited from buying firearms.

In August, a 5-4 court sided with the Biden administration in a challenge brought by a group of manufacturers and allowed the regulations to remain in effect while legal challenges play out.

After the order was issued, however, US district Judge Reed O'Connor stepped in to block the regulations as applied to two manufacturers. The injunction was largely upheld by the 5th US Circuit Court of Appeals.

In an unusually sharp filing, Solicitor General Elizabeth Prelogar told the justices on Thursday that the district court and the Fifth Circuit "have effectively countermanded this Court's authoritative determination about the status quo that should prevail during appellate proceedings in this case."

"In doing so, the lower courts openly relied on arguments that this Court had necessarily rejected," Prelogar said, adding that the court "should not tolerate that affront."

"This is the rare application where this Court has already applied the relevant legal standard in the very same case and determined the government should obtain emergency relief," she said. "The Court's answer should be the same as it was two months ago."

In 2022, the Bureau of Alcohol, Tobacco, Firearms and Explosives updated its regulations to define the kits as firearms under the law so that the government could more carefully track them.

The rule does not prohibit the sale or possession of any ghost gun kit, nor does it block an individual from purchasing such a kit. Instead, it requires compliance with federal laws that impose conditions on the commercial sale of firearms. Those conditions include requirements that commercial manufacturers and sellers mark products with serial numbers and keep records to allow law enforcement to trace firearms used in crimes.