The United States Embassy in Afghanistan's Kabul has warned American citizens to keep clear of Hamid Karzai International Airport while citing security threats that were not explained, according to US media reports. The Embassy also advised everyone who waits outside the premises of the airport to "leave immediately".

Even though no details were given about the potential security threat in the area, officials from the Embassy three areas that need to clear.

"US citizens who are at the Abbey Gate, East Gate, or North Gate now should leave immediately", the statement from the United States embassy said, according to reports from the New York Times.

Select entry points to the Hamid Karzai International Airport, where the United States and allied countries have maintained a stronghold to conduct evacuation flights, have been temporarily sealed off due to the multiple security warnings.

The British government has also warned its citizens in Afghanistan to stay away from the international airport in Kabul, citing the “ongoing and high threat” of a terrorist attack.

The Foreign Office says anyone in the area of the airport should “move away to a safe location and await further advice", according to reports from Associated Press.

Earlier on Wednesday, US Secretary of State Antony Blinken suggested that the airlift from Afghanistan was far from over. He said that as many as 1,500 Americans may be awaiting evacuation from the Taliban-controlled country.

In a news conference, Blinken said the State Department estimates there were about 6,000 Americans who wanted to leave Afghanistan when the airlift began August 14, when the Taliban reached Kabul, and that about 4,500 of them have been evacuated so far.

Since August 14, when the Taliban seized the Afghan capital of Kabul, more than 82,000 people have been evacuated from the country in one of the biggest US airlifts in history, according to reports from Associated Press.