Now nearly 20-year-old conflict has reportedly cost US an estimated $2.26 trillion

'Save the Children' notes in its report South Asian nation is among the 11 most dangerous countries

World Bank's country director Sunday urged Afghan leaders to invest more in their people and stresse

The announcement comes as the Afghan government and the Taliban declare a three-day cease-fire coinc

The UN blames militants for most of the deaths, followed by the US-led coalition