A militant group rejected Joe Biden’s claim he could extend the deadline to evacuate U.S. forces from Afghanistan.

The Taliban declared the president was wrong to suggest U.S. troops, citizens, and asylum seekers might be permitted to leave after Aug. 31.

“If the United States or United Kingdom were to seek additional time to continue evacuations–the answer is no, or there would be consequences,” spokesman Suhail Shaheen said according to Sky News.

Shaheen described Biden’s original promise to withdraw before the end of the month as a “red line” that cannot be crossed.

“President Biden announced that on 31 August they would withdraw all their military forces so, if they extend it, that means they are extending occupation while there is no need for that,” he said according to the broadcaster.

The remarks came after the Democrat claimed he was very confident the U.S. evacuation is on-track, and did not rule out an extension.

“We see no reason why this tempo will not be kept up,” he said in a statement. “There are discussions going on among us and the military about extending. Our hope is we will not have to extend but there are going to be discussions, I suspect, on how far along we are in the process.”

UK Prime Minister Boris Johnson will plead with his U.S. counterpart at an upcoming G7 summit to try to secure an extension, following recent chaos and mayhem at Hamid Karzai International Airport.

However, the Taliban is unlikely to cooperate with any such request as the group shows zero tolerance to tardiness.

“It will create mistrust between us, if they are intent on continuing the occupation it will provoke a reaction,” Shaheen said according to the broadcaster.

The looming deadline has exacerbated desperation among Afghans who want to flee Taliban violence. A growing number of reports have emerged of fighters seeking vengeance and murdering Afghan people at home for helping U.S.-led foreign forces.

The United States evacuated an estimated 11,000 people in just 30 hours at the weekend. A total of 28,000 U.S. nationals, allies, and Afghans have been safeguarded, with 33,000 people transported since the Taliban seized control of the presidential palace on Aug. 15.

Not every Biden administration official is upbeat about the evacuation’s progress.

“I have said all along that no nation will be able to get everyone out,” Defence Secretary Ben Wallace said according to Sky News. “It is a source of deep sadness for many of us across [the] North Atlantic Treaty Organization and no one wanted 20 years of sacrifice to end this way, … we will do our best to the very last moment.”