The Taliban’s blitz across Afghanistan pushed to within miles of Kabul on Saturday, as remaining towns and provinces continued to fall to the militants with a speed that seemed inconceivable just a week ago.

With the Afghan capital among the few areas left to conquer, President Biden warned that any moves to threaten American personnel or interests there would be met with a “swift and strong” U.S. military response from thousands of American troops flooding into the city.

Biden, in his first public statement since the administration on Thursday announced the deployment of 3,000 troops to aid in the evacuation of American diplomats and civilians and Afghans who have aided the U.S. government, said the force being dispatched to Kabul would grow to 5,000.

On Aug. 14, President Biden approved additional military forces to help safely draw down the American embassy and remove personnel from Afghanistan. (Reuters)

The difference, according to a Defense official, reflected an additional 1,000 troops the president on Saturday authorized to be sent to Kabul from a force being held at the ready in Kuwait in case they were needed, and at least 650 more who had stayed behind after the U.S. military withdrawal with a narrow mission of protecting the U.S. Embassy and airport.

The increased deployment came as U.S. diplomats appealed to the Taliban to halt its advance or risk a direct confrontation with the American force.

In Doha, Qatar — where just two days before representatives of world and regional powers had gathered to warn the militants that the world would cut them off from any legitimacy or aid if they took over Kabul by force — administration envoy Zalmay Khalilzad was left with Taliban officials who countered his entreaty with their own demand for an end to escalating U.S. airstrikes trying to delay their advance.

Biden said his message about a U.S. military response to “any action on the ground … that puts U.S. personnel or our mission at risk there” had been conveyed to the Taliban in Doha “via our combatant commander” for the region.

The fate of Afghanistan’s Western-backed government also hung in the balance. President Ashraf Ghani, in his first public appearance since the Taliban’s stunning sweep took hold, told Afghans he was turning to the international community for help, even as events appeared to be overtaking him and his administration.

Afghan President Ashraf Ghani said on Aug. 14 he was in talks with local and international partners as Taliban rebels approached Kabul, the country's capital. (Reuters)

By late Saturday, Taliban fighters had broken the defenses of northern Afghanistan’s main city, Mazar-e Sharif, where Ghani had flown days earlier to rally pro-government forces, giving the insurgents full hold of the north and critical routes to Central Asia.

Abas Ebrahimzada, a lawmaker from Balkh province, where the city is located, told the Associated Press that the army first surrendered in Mazar-e Sharif amid a multipronged assault by the Taliban, leading pro-government militias to lay down their weapons.

Earlier in the day, the Taliban appeared to have gained full control of Logar province, bringing fighters as close as seven miles from Kabul, a provincial lawmaker, Hoda Ahmadi, told the AP. Logar’s flatlands, ringed by mountains, serve as an important gateway to the capital, with roadways connecting to cities to the south.

The insurgents on Saturday also seized the capital of Paktika, an eastern province bordering Pakistan, lawmaker Khalid Asad confirmed to the AP. Asad said fighting had broken out in the capital, Sharana, and lasted until local elders intervened to negotiate a pullout. Local officials, including the governor, left for Kabul after surrendering.

The numerous battlefronts have pushed Afghanistan toward a potential humanitarian catastrophe, as tens of thousands of people flee their homes amid the swift insurgent advances.

In Kabul, scenes were reminiscent of the Taliban’s rise in the mid-1990s — with families selling their possessions and doing whatever they could to flee the country. Many fear a return to the repressive and brutal rule the Taliban inflicted when it was last in power, rooted in an extreme interpretation of Islamic law. Civilians in areas of Taliban control elsewhere were already reporting shuttered girls’ schools, poor families forced to cook food for ravenous fighters and young men pressured to join the ranks of the militants.

In a statement taking stock of its battlefield victories, the Taliban on Saturday sought to project itself as Afghanistan’s rightful ruler, appealing for calm and claiming no harm would come to those who have aided the American-led military campaign over the 20-year war or held jobs in the central government. Rather, those people would be granted “amnesty,” it said.

“We assure all our neighbors that we will not create any problems for them,” the statement asserted. “We also assure all the diplomats, embassies, consulates, and charitable workers, whether they are international or national that not only no problems will be created for them … but security and a secure environment will be provided to them.”

That message would be more believable, U.S. officials said the Taliban was told, if the militants avoid interfering with U.S. troops in Kabul, and waited until the United States and other evacuating diplomatic missions completed the departure. The militants, who have said repeatedly they do not want to be isolated from the world, would then have ample opportunity to prove their intentions by entering the city without violence.

Both the departure of U.S. civilian personnel, ordered by Biden on Thursday, and the final withdrawal of all U.S. forces based in Afghanistan, are scheduled to be completed by Aug. 31, administration officials have said.

Ghani’s government has proposed presenting the Taliban with a new power-sharing plan in the coming week during their diplomatic negotiations in Doha, where sputtering inter-Afghan talks have gone on for nearly a year. But that timetable was seen as unrealistic amid the fast-shifting developments, according to people familiar with the situation who spoke on the condition of anonymity to discuss the unfolding events.

Any political settlement at this point is likely to be tantamount to full Taliban control, even if it includes elements of power-sharing with nonmilitant political figures and power brokers. The Taliban has been adamant throughout the earlier talks that Ghani cannot remain in power.

Ghani’s recorded address, aired on national television Saturday, appeared in part to be directed toward boosting the rapidly flagging morale and effectiveness of Afghanistan’s security forces. While the Americans want at all costs to avoid a direct confrontation between the Taliban and U.S. troops, the extent to which the Afghan military will resist the militants’ entry into Kabul is unclear.

Ghani said he was in talks with international partners and political groups inside the country in an effort not to “lose the gains of the past 20 years.”

He did not offer specifics on what he expected from world leaders, other than to say that his first priority was “organizing the Afghan forces” — many of which have crumbled in the face of the rapid insurgent advance in recent days. He said consultations had also begun with Afghan elders and political leaders. “Soon the results will be shared with you,” Ghani said.

Ghani expressed concern about the thousands of displaced Afghans who have fled to the relative safety of Kabul in recent weeks, and the likelihood of a fresh wave of refugees moving into neighboring countries and beyond.

Biden said in his statement that he had directed Secretary of State Antony Blinken to support Ghani and other Afghan leaders “as they seek to prevent further bloodshed and pursue a political settlement,” and would also engage with “regional stakeholders.” Blinken, in a call Saturday to Ghani, “discussed the urgency” of efforts to stem the violence, State Department spokesman Ned Price said. The secretary also “emphasized the United States’ commitment to a strong diplomatic and security relationship with the Government of Afghanistan and our continuing support for the people of Afghanistan.”

Repeating remarks he has made since he first announced a U.S. exit from Afghanistan in April, Biden indicated he still planned a full withdrawal. Recalling that he had “inherited a [withdrawal] deal cut by my predecessor,” former president Donald Trump, he said that “one more year, or five more years, of U.S. military presence would not have made a difference” if the U.S.-trained, equipped and paid Afghan military “cannot or will not hold its own country.”

Pannett reported from Sydney, George from Kabul, and Westfall and DeYoung from Washington. Ezzatullah Mehrdad in Kabul and Dan Lamothe in Washington contributed to this report.