The US embassy in Kabul advised American citizens today that the US government cannot ensure safe passage to the airport for those looking to flee the country.

“THE UNITED STATES GOVERNMENT CANNOT ENSURE SAFE PASSAGE TO THE HAMID KARZAI INTERNATIONAL AIRPORT,” the embassy advised American citizens in a security alert Wednesday.

The alert told citizens that space on evacuation flights will now be available “on a first come, first serve basis.”

Some context: The guidance seemed to mark a significant shift from previous advisories, which told US citizens to shelter in place until they were advised by the embassy to report to the airport.

The message about the inability to ensure safe passage to the airport comes in stark contrast to comments made by National Security Adviser Jake Sullivan just a day prior. He told reporters Tuesday that the Taliban had committed to allowing safe passage for civilians to the airport.

Wednesday’s alert noted, “U.S. citizens, LPRs, and their spouses and unmarried children (under age 21) should consider travelling to Hamid Karzai International Airport,” but advises that “you may be required to wait at the airport for a significant amount of time until space is available.”