US President Joe Biden said Tuesday that he does "not regret" his decision to withdraw troops from Afghanistan. "We spent over one trillion dollars over 20 years. We trained and equipped with modern equipment over 300,000 Afghan forces," Biden told reporters at the White House. "We lost .. in death and injury thousands of American personnel". He stressed, "Afghan leaders have to come together," adding "they've got to fight for themselves, fight for their nation". He reiterated, "they've got to want to fight. They have outnumbered the Taliban." "I think they're beginning to realize they got to come together politically at the top," he stated, adding, "We're going to continue to keep our commitment. But I do not regret my decision." Biden affirmed that the US will "continue to keep the commitments we made of providing close air support, making sure that their air force functions and is operable, re-supplying their forces with food and equipment and paying all their salaries." According to media reports, the Taliban seized a fifth Afghan provincial capital in the north on Monday, a day after they seized three more provincial capitals of Afghanistan. A US-led military campaign began in 2001 following the 9/11 attacks on American soil —but now most of the foreign troops have pulled out. The Taliban has now seized nine of the country's 34 provincial capitals, and are threatening more. The Washington Post cited unnamed officials as saying the capital Kabul could fall to the Taliban within 90 days, based on US military assessments. More than 1,000 civilians have been killed amid fierce fighting between the Taliban and government forces in the past month, according to the UN. Its children's agency UNICEF warned this week that atrocities being committed against children were growing "higher by the day". In their latest major advances, Taliban militants seized three more provincial capitals in 24 hours — Faizabad, Farah and Pul-e-Khumri. Officials said that on Tuesday the insurgents had raised their flag in the main square and on the governor's office in Pul-e-Khumri, the capital of Baghlan province, which is located about 200km (125 miles) from Kabul. A local journalist and provincial council member told the BBC that the western city of Farah had fallen. And on Wednesday, the Taliban claimed to have taken Faizabad in the north-west of the country. Other gains by the militant group this week include the key northern city of Kunduz. It is considered a gateway to mineral-rich provinces and is in a strategically important location close to the border with Tajikistan. Heavy fighting is continuing in other parts of the country, and US and Afghan planes have been carrying out airstrikes. On Wednesday Afghanistan's President Ashraf Ghani flew to Mazar-i-Sharif in an apparent drive to rally the defenders in the key northern city, which is now threatened by the militants. — Agencies