In photos: As Taliban advance in Afghanistan the U.N. warns of a humanitarian catastrophe
U.N. agencies warns of a humanitarian catastrophe in Afghanistan as Taliban advances drive tens of thousands of people from their homes amid spreading hunger. Insurgents have taken control of the second- and third-biggest cities as Western embassies prepared to send in troops to help evacuate staff, although the United Nations said its 320 staff members would remain.

A Taliban fighter stands guard over surrendered Afghan security member forces in the city of Ghazni, southwest of Kabul, Afghanistan.Gulabuddin Amiri/The Associated Press

Taliban fighters stand guard over surrendered Afghan security members forces in the city of Ghazni, southwest of Kabul, Afghanistan.Gulabuddin Amiri/The Associated Press

Kabul police secure the roads with police checkpoints in Kabul, Afghanistan. Tensions are high as the Taliban advance on the capital city after taking Herat and the country's second-largest city Kandahar.Paula Bronstein./Getty Images

Kabul police secure the road in the central part of the city in Kabul, Afghanistan.Paula Bronstein/Getty Images

Displaced Afghan women and children from Kunduz are seen at a mosque that is sheltering them in Kabul, Afghanistan.Paula Bronstein/Getty Images

Taliban fighters stand guard inside the city of Ghazni, southwest of Kabul, Afghanistan.Gulabuddin Amiri/The Associated Press

Afghan military and police vehicles are parked at the army base in Kandahar during fighting between the Taliban and Afghan security personnel in the province, southwest of Kabul.Sidiqullah Khan/The Associated Press

Taliban fighters patrol inside the city of Ghazni, southwest of Kabul, Afghanistan.Gulabuddin Amiri/The Associated Press

Pakistani soldiers stand guard while stranded people walk towards the Afghan side at a border crossing point, in Chaman, Pakistan. Pakistan opened its Chaman border crossing for people who had been stranded in recent weeks. Juma Khan, the Pakistan border town's deputy commissioner, said the crossing was reopened following talks with the Taliban.Jafar Khan/The Associated Press

An Afghan policeman stands guard as internally displaced Afghan people, who fled from the northern province due to battle between Taliban and Afghan security forces, prepare to gather to receive free food being distributed by Shiite men at Shahr-e-Naw Park in Kabul.WAKIL KOHSAR/AFP/Getty Images

Internally displaced Afghan people, who fled from the northern province due to battle between Taliban and Afghan security forces, gather to receive free food being distributed by Shiite men at Shahr-e-Naw Park in Kabul.WAKIL KOHSAR/AFP/Getty Images

Afghan families, who fled from the northern province due to battle between Taliban and Afghan security forces, sit next to temporary tents in the courtyard of the Wazir Akbar Khan mosque in Kabul.WAKIL KOHSAR/AFP/Getty Images

Internally displaced Afghan families, who fled from the northern province due to battle between Taliban and Afghan security forces, sit in the courtyard of the Wazir Akbar Khan mosque in Kabul.WAKIL KOHSAR/AFP/Getty Images

Taliban fighters patrol inside the city of Ghazni, southwest of Kabul, Afghanistan.Gulabuddin Amiri/The Associated Press

Supporters of the hardline pro-Taliban party Jamiat Ulema-i-Islam-Nazaryati (JUI-N) eat sweets as they celebrate the capture of cities in Afghanistan by the Taliban, in Quetta.BANARAS KHAN/AFP/Getty Images

Taliban fighters patrol inside the city of Ghazni, southwest of Kabul, Afghanistan.Gulabuddin Amiri/The Associated Press

Smoke rises after fighting between the Taliban and Afghan security personnel, in Kandahar, southwest of Kabul, Afghanistan.Sidiqullah Khan/The Associated Press

Taliban fighters drive an Afghan National Army (ANA) vehicle through a street in Kandahar.-/AFP/Getty Images

Taliban fighters stand on a vehicle along the roadside in Kandahar.-/AFP/Getty Images

Afghan military and officials leave Kandahar city during fighting between the Taliban and Afghan security personnel, in Kandahar, southwest of Kabul.Sidiqullah Khan/The Associated Press

Smoke rises after fighting between the Taliban and Afghan security personnel, in Kandahar, southwest of Kabul, Afghanistan.Sidiqullah Khan/The Associated Press

Stranded people cross the border between Pakistan and Afghanistan, in Chaman, Pakistan.Jafar Khan/The Associated Press