New Delhi, Oct 19 : Zalmay Khalilzad, who served as the US Special Representative for Afghanistan Reconciliation since September 2018, has stepped down, Secretary of State Antony Blinken announced. Taking to Twitter on Monday night, Blinken said: "Thank you to Ambassador Zalmay Khalilzad for decades of tireless service to the United States. Pleased to welcome Thomas West to the role of Special Representative for Afghanistan." TOLO News shared Khalilzad's resignation letter to Blinken, in which the former diplomat wrote: "Today, our forces are out, the war is finally over for the United States and the very high financial costs of this engagement can now be directed to other vital needs. However, the political arrangement between the Afghan government and the Taliban did not go forward as envisaged. "The reasons for this are too complex and I will share my thoughts in the coming days and weeks, after leaving government service." The move came two months after the hasty withdrawal of American forces from Afghanistan. "I am of course saddened on behalf of the Afghan people that, despite our best efforts and extensive shuttle diplomacy on my part and that of the team as well as much urging from the international community, the Afghans failed to make use of this opportunity to end their 40-year conflict in a constructive spirit and with a fair compromise," Khalilzad added in the leader. Khalilzad, a leading US diplomat of Afghan-origin, has long been a controversial figure for his involvement in Washington's 'War on Terror'. He also led Washington's talks with the Taliban, which many see as the main precursor to the Pashtun-dominated group's lightning victory in Afghanistan, TRT World reported. After the Taliban's surprisingly quick victory against the US-trained Afghan army, many government operators and experts can't help but speculate on Washington's role, particularly that of Khalilzad, in the Afghan group's return to power. Some other experts further believe that Khalilzad pursued a "special political agenda" to promote his personal and family interests. "One man responsible for the chaos and destruction raging across Afghanistan is Zalmay Khalilzad. He should be investigated for alleged financial corruption," says Kamal Alam, a non-resident senior fellow at the Atlantic Council. In 2014, Khalilzad's finances were subject to an Austrian investigation which froze his wife's accounts in the European country based on information from the US Department of Justice that he was suspected of money laundering related to business activities in Iraq and the United Arab Emirates (UAE). "This man wanted to be the president of Afghanistan. He ran to be the president of Afghanistan. No one likes him. Everyone hates him," Alam tells TRT World. /IANS