WASHINGTON, Aug 30 (Reuters) - The United States will continue its "relentless efforts" to help people leave Afghanistan if they choose to, said Secretary of State Antony Blinken on Monday (Aug 30).

Blinken’s statement comes after the departure of the last US plane, leaving behind thousands of Afghans who helped Western countries and might have qualified for evacuation.

"A new chapter of America's engagement with Afghanistan has begun. It's one in which we will lead with our diplomacy," Blinken said.

"We will continue our relentless efforts to help Americans, foreign nationals and Afghans leave Afghanistan, if they choose," he added.

Close to more than 100 Americans were still believed to remain in Afghanistan who wanted to leave but Washington was trying to determine their exact number, said Blinken.

More than 6,000 Americans have been evacuated.

At least 122,000 people have been flown out of Kabul since Aug 14, the day before the Taliban - which harboured the Al-Qaeda militant group blamed for the 2001 attacks on New York and Washington - regained control of the country.

As the fate of the Kabul airport, the country's main gateway to the rest of the world, remained uncertain following the US departure and Taliban takeover, Blinken said Washington was working to find ways to help Americans and others who may choose to depart via overland routes.

"We have no illusion that any of this will be easy or rapid," he said.