WASHINGTON, Aug 24 (CNBC) – The Taliban said Tuesday that the group will not allow Afghan nationals to leave the country and opposes any extension of evacuation flights, a development that comes one week before U.S. and coalition forces are slated to depart Afghanistan.

“We are not in favor of allowing Afghans to leave,” Taliban spokesman Zabihullah Mujahid told reporters during a news conference Tuesday.

“They [the Americans] have the opportunity, they have all the resources, they can take all the people that belong to them but we are not going to allow Afghans to leave and we will not extend the deadline,” he said, adding that evacuations carried out by foreign forces after Aug. 31 would be a “violation” of a Biden administration promise to end the U.S. military’s mission in the country.

“The way to the airport has been closed now. Afghans are not allowed to go there now, foreigners are allowed to go but we have stopped Afghan nationals to go because the crowd is more, there is danger that people will lose their lives, there might be a stampede,” Mujahid said, according to an interpreter during the broadcast.

Pentagon spokesman John Kirby told reporters on Tuesday that there has not been a change to the timeline of the mission.

“We remain committed to getting any and all Americans that want to leave out and we still believe certainly now that we have been able to increase the capacity and the flow, we believe that we have the capability, the ability to get that done by the end of the month,” Kirby said.

“The Taliban have been very clear about what their expectations are,” explained Kirby when asked about public Taliban statements opposing a prolonged U.S. military mission in Afghanistan.

“Without getting into details, I’m not seeing much dissonance [between public and private conversations with Taliban],” he added.

On Monday, a Taliban spokesman issued a similar warning during an interview with Sky News in regard to a potential extension.

“It’s a red line. 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,” Suhail Shaheen said, according to the report.

“If the U.S. or U.K. were to seek additional time to continue evacuations, the answer is no. Or there would be consequences,” he added.

U.S. President Joe Biden declared Tuesday he is sticking to his Aug. 31 deadline for completing a risky airlift of Americans, endangered Afghans and others seeking to escape Taliban-controlled Afghanistan. The decision defies allied leaders who want to give the evacuation more time and opens Biden to criticism that he caved to Taliban deadline demands.