US National Security Adviser Jake Sullivan has said that the US is engaging with the Taliban on a daily basis as the ongoing Afghan evacuation faces the August 31 deadline.

President Joe Biden has left open the possibility of extending the ongoing evacuation beyond August 31, the date he previously set to end the US military mission in Afghanistan, Xinhua news agency reported on Tuesday.

Taliban spokesman Suhail Shaheen, however, made clear in an interview with Sky News that such extension would be unacceptable.

At a White House briefing on Monday, Sullivan told reporters that the US has been consulting with allies and the Taliban on the evacuation issues.

“We are in talks with the Taliban on a daily basis through both political and security channels,” he said when asked about talks with the Taliban over the extension issue. “I’m not going to get into the details of those discussions here to protect those discussions, which are covering a wide range of issues.”

Sullivan added that the US is consulting the Taliban “on every aspect of what’s happening in Kabul right now” and would continue those conversations.

“As the president has said before, we believe that we have time between now and the 31st to get out any American that wants to get out,” he said, while noting “the president will ultimately make his decision about the precise shape and scope of this operation.”

State Department spokesperson Ned Price said later in the day that the US had discussed the issue of Kabul airport with the Taliban.

“There is actually an agreement between and among all these actors, of course between the US and our partners and allies, but also with the Taliban, that all of our interests would be served with a functioning airport,” he told reporters during a daily briefing.

According to media reports, British Prime Minister Boris Johnson would use the virtual summit of Group of Seven (G7) held on Tuesday to push Biden to extend the August 31 deadline to exit the country.

French Foreign Minister Jean-Yves Le Drian also said that additional time is needed to complete the evacuation.

The US and its allies have been scrambling to evacuate personnel from Afghanistan since the Taliban entered Kabul on August 15.

Sullivan said the US and coalition aircraft had evacuated over 16,000 people in the last 24 hours.