Six Afghan provincial capitals have fallen to the Taliban since Friday, Reuters notes, with the militants taking the town of Aybak on Monday and targeting northern Afghanistan's largest city, Mazar-i-Sharif.

Why it matters: The string of swift Taliban successes in the final weeks of the U.S. withdrawal has dented hopes that the Afghan military and allied militias will be able to fend off the insurgency.

• 229 Afghan districts are now under Taliban control, 66 are controlled by the government, and 112 are contested, per the Long War Journal. Most of the initial gains were in the countryside, but the Taliban is now targeting major cities.

Flashback: As of June 16, the Taliban and government controlled a roughly equal number of districts (104 and 94, respectively) with 201 contested.

• The Taliban is also targeting senior officials for assassination. Dawa Khan Menapal, who ran the government's media department, was killed on Friday, shortly after a failed assassination attempt on Afghanistan's defense minister.

What they're saying: The United Kingdom's Defense Secretary Ben Wallace was the latest to question the decision of the U.S. and NATO forces to rapidly withdraw before the 20th anniversary of the Sept. 11 attacks.

• He told the Daily Mail that the U.K. had sought an agreement for some NATO troops to remain but "without the United States as the framework nation it had been, these options were closed off."
• A Pentagon spokesperson said Monday that "these are their provincial capitals" and it's up to the Afghan government to defend them.

What to watch: Afghan officials are seeking continued U.S. air support after the withdrawal, but the Pentagon hasn't said whether and how it would conduct such operations.