United States Secretary of State Antony Blinken disputed claims that the Taliban insurgents in Afghanistan are blocking those with valid travel documents from leaving the country.

Blinken confirmed Tuesday the Taliban had grounded the planes because others whose names appear on manifest documents for flights could not show proof of any valid travel papers.

There are a "small number" of American nationals in Afghanistan's northern city of Mazar-e-Sharif. who have been unable to be airlifted on chartered flights.

"There are some people grouped together, some of whom with appropriate travel documents... and others do not," Blinken said in quotes by Politico during a news briefing in Doha, Qatar.

Some critics have rejected Blinken's statement, saying the Biden administration must exert more effort to get these planes out of Afghanistan and help American nationals and vulnerable Afghans.

Blinked pointed out that the Taliban has not denied exit to anyone with valid travel papers, adding the Taliban have made it clear that those without valid documents at this point can't leave the country.

The chartered planes for around 600 people have been grounded at Mazar-e-Sharif's airport for more than a week now, sources said, with at almost 20 American citizens waiting in the city to board a flight out of Afghanistan.

Other reports indicate more than 1,000 people, including some Americans, are still held at the airport in northern Afghanistan. Jen Psaki, White House press secretary, disclosed that just "under 100" U.S. nationals were stranded in the country.

Blinken said the state department has been "working round the clock" with non-government organizations with members of Congress, and advocacy groups and carrying out a "great deal of diplomacy" on the matter, including with leaders of the Taliban.

Both Psaki and Blinken denied claims by Texas Rep. Michael McCaul that the insurgent group was holding U.S. nationals and Afghan allies at the airport hostage until the U.S. government recognized the Taliban as the rightful rulers of Afghanistan.

"Those were claims made by a Republican congressman this weekend," Psaki said, adding they are in touch with American citizens and are working to get them out of the country.