Taliban fighters stand over a damaged police vehicle along the roadside in Kandahar on August 13, 2021.

AFP | Getty Images

The Taliban overtook two of Afghanistan’s largest cities, the latest conquests for the insurgents who are rapidly wresting control of the country just weeks before the U.S. was set to complete its withdrawal of troops there.

Islamist militants captured Kandahar, the second-most populous city in the country, as well as the third-largest city of Herat, NBC News reported Friday, citing a Taliban spokesman and local Afghan officials.

The insurgents have now seized at least half of Afghanistan’s 34 provincial capitals, taking control of roughly two-thirds of the nation and encircling Kabul, where the U.S. Embassy is preparing to evacuate all but its core diplomatic personnel.

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Afghan government security forces have crumpled and many civilians have fled their homes amid the Taliban’s surprisingly swift advance toward the nation’s power center.

But the White House on Friday morning said Biden stands by his decision to end the U.S. presence in Afghanistan after nearly two decades of fighting in the wake of the 9/11 terrorist attacks.

“The President is firmly focused on how we can continue to execute an orderly drawdown and protect our men and women serving in Afghanistan,” White House press secretary Jen Psaki said in a statement.

“You heard him earlier this week: he does not regret his decision,” Psaki said.

In addition to the deployment of three infantry battalions from the Marines and Army to Kabul, a U.S. infantry brigade will be positioned on standby in Kuwait. Another 1,000-member unit comprising Army and Air Force personnel will deploy to Qatar to help process special immigrant visas for Afghan nationals who assisted U.S. and NATO troops during the war.

US national flag is reflected on the windows of the US embassy building in Kabul on July 30, 2021.

Sajjad Hussain | AFP | Getty Images

Nevertheless, Pentagon spokesman John Kirby said Thursday that the U.S. still expects to fully withdraw all troops by the end of August.

Britain said Thursday it will send about 600 troops to help its citizens leave Afghanistan, where about 4,000 U.K. nationals are believed to be stationed. Canada is also deploying special forces to the country to evacuate staff in the Canadian Embassy in Kabul.

This is developing news. Please check back for updates.

— CNBC’s Amanda Macias contributed to this report.