Washington, Aug 14 : The Pentagon has said that Afghan Taliban militants are trying to isolate the capital city Kabul and the situation on the ground is "deeply concerning". "We are certainly concerned by the speed with which the Taliban has been moving," Pentagon Press Secretary John Kirby told reporters on Friday in a press briefing. "It's deeply concerning." He said that the insurgent group is trying to isolate Kabul, while noting the capital city currently is not "in an imminent threat environment", Xinhua news agency reported. He reiterated that the Afghan forces, which the US will continue to support, are capable of making a difference on the ground. "This is a moment for the Afghans to unite, the leadership and in the military. No outcome has to be inevitable here." The Pentagon announced Thursday that three infantry battalions, about 3,000 troops, will be deployed to Kabul airport within 48 hours to support US embassy staff reduction and Afghan Special Immigrant Visas (SIV) applicants evacuation given the Taliban's rapid offensive across the country. "Some elements of one of the Marine infantry battalions are already there in Kabul," Kirby said. "And I expect that by the end of the weekend the bulk of the 3,000... will be in place." The US Transportation Command is developing airlift plans with Central Command to support the mission, he added. "Our intention is to be able to move thousands per day." The Taliban said it captured another three provincial capitals on Friday. Logar province's capital city Pul-e-Alam, which was seized by the Taliban earlier in the day, is just about 60 km from Kabul. CNN reported on Friday that the US Embassy in Kabul is instructing personnel to destroy sensitive materials and items like embassy logos and American flags "which could be misused in propaganda efforts." The State Department said it was part of the standard procedure applied when minimizing the US footprint. State Department spokesperson Ned Price said Thursday that US personnel in Kabul will reduce to "a core diplomatic presence" in the coming weeks. The situation in the war-torn country has been worsening since the withdrawal of US-led troops starting on May 1. Many Afghan cities and about half of the country's 34 provinces in recent weeks have seen heavy battles and street fighting between Afghan forces and Taliban militants. President Joe Biden ordered the US military to end its mission in Afghanistan by the end of this month, and he said he did not regret the pullout decision earlier this week. /IANS