With Afghan cities falling to the Taliban day after day, the U.S. is sending in more troops — to help evacuate American diplomats.

Driving the news: The State Department announced today that it will shrink down to a "core diplomatic presence" in Kabul due to the deteriorating security situation. The Pentagon is sending 3,000 troops to Afghanistan's international airport to assist in that mission and help get Afghans who worked with U.S. troops out of the country.

Behind the scenes: President Biden brought together his senior national security team last night for a briefing on Afghanistan, and by this morning, there was a unanimous decision to send in troops and partially evacuate the embassy.

What they're saying: State Department spokesperson Ned Price attempted to downplay the announcement, insisting that it "shouldn’t be read as any sort of message to the Taliban."

• The Biden administration continues to insist that the Taliban will sacrifice any future international legitimacy if it takes power by force and points to the negotiating table in Doha, Qatar, as the true path forward.
• Such statements sound increasingly futile as the Afghan government's hold on the country evaporates by the hour.
• But Biden has said he has no regrets about his decision to withdraw, and he put the onus on Afghanistan's civilian and military leaders to turn back the Taliban, contending that they still have superior manpower and resources.

A WhatsApp message circulating among senior Afghan military officials over the last 48 hours suggests some hope of a counterattack and the desire for additional U.S. air support.

• "We need more air power. The Taliban are out in the open. ... They could not be more exposed," read the message. "Two weeks of proper support would mean we get them to the negotiating table and reverse their progress."
• "Remember after 9/11, with good air support, Taliban lost the entire country in two weeks," a senior military leader wrote, pressing his colleagues to push for more help from Washington.
• The Pentagon has said it will provide air support "where and when feasible," in the coming weeks, but hasn't said whether any air support will continue after Aug. 31. U.S. officials note that airstrikes are less effective when the fighting is in heavily populated areas.

What's next: In total, the Pentagon is mobilizing upward of 7,000 troops for the evacuation mission.

• In addition to the roughly 3,000 infantry soldiers set to arrive at the airport in the next 48 hours, additional troops will be sent to Qatar to help manage the evacuation of Afghans seeking special immigrant visas.
• Another infantry brigade will be sent from the U.S. to Kuwait to be prepared to provide “additional security at the airport” as needed.
• Pentagon press secretary John Kirby said the partial evacuation of the embassy would be completed by the end of this month, when the U.S. military mission in Afghanistan is also set to end.

Worth noting: Price declined to say how many diplomats would remain in the embassy or whether there was any consideration of moving the embassy to a more secure location.

Meanwhile, the Taliban today took Afghanistan's second and third largest cities and the provincial capital closest to Kabul.

The big picture: That brings the number of provincial capitals captured over the last week to 12, an astounding number considering the group didn't hold a single major city prior to last Friday. The Taliban now controls more than two-thirds of Afghanistan's territory.

• The capture of Ghazni puts the front lines within 100 miles of Kabul and cuts off a key highway linking the capital with Afghanistan's southern provinces.

The fall of Kandahar, Afghanistan's second-largest city and the birthplace of the Taliban movement, is more significant still.

• The Taliban first seized Kandahar in the 1990s before toppling the Afghan government in Kabul and declaring an Islamic state.
• They were driven out of the city of 600,000 during the U.S.-led invasion of Afghanistan in 2001.

A new U.S. intelligence assessment suggests that Kabul could fall to the Taliban within 30–90 days — a stark revision from a previous assessment that the capital could possibly fall 6–12 months after the U.S. withdrawal.

• U.S. officials admit that they've been surprised at the unprecedented pace of the offensive and the decision by so many Afghan forces to abandon the battlefield.

Go deeper:Inside the Biden administration as Afghanistan collapses