[6] On 3 January 2020, the United States conducted an airstrike that killed Iranian Major General Qasem Soleimani and Kata'ib Hezbollah commander Abu Mahdi al-Muhandis.

In February 2021, NATO announced it would expand its mission to train Iraqi forces in their fight against ISIL,[14] partially reversing the U.S.-led troop withdrawals.

In April 2021, U.S. Central Command stated that there were no plans for a total withdrawal of U.S. forces from Iraq, citing continued threats posed by the ISIL insurgency and Iran-backed militias.

[10] Qais Khazali, leader of Iranian proxy group Asa'ib Ahl al-Haq, stated "If [US troops] don't leave, then they will be considered occupation forces.

[15] According to a letter sent by a senior U.S. commander to Iraqi officials on 6 January 2020, "the United States may be preparing to withdraw its troops",[17] but after a while Chairman of the Joint Chiefs Gen. Mark Milley, announced that it was a draft sent by "honest mistake.

"[18] On 8 January 2020, Iran launched "Operation Martyr Soleimani", conducting missile strikes against U.S. troops stationed in Iraq.

[21] Due to security concerns, some NATO countries including Canada, Germany, Croatia and Slovakia said they were concluding their training missions and pulling troops out of Iraq, at least temporarily.

[23] The United States responded to the first attack on Camp Taji by targeting five Kata'ib Hezbollah weapon storage facilities with air strikes.

[26] On that same day, United States Central Command ordered a 14-day "stop movement" preventing any U.S. troops from entering or leaving Iraq and Afghanistan because of the pandemic.

"[29] However, an inspector general report released in May 2020 admitted that though the base transfers were planned ahead of time, they were accelerated due to the threat of Iranian proxies and the pandemic.

[32] On 9 June 2020, prior to the start of the dialogue, a rocket attack against U.S. troops in Baghdad International Airport concluded with no injuries.

Moreover, Christopher C. Miller, the former acting Defense Secretary, noted that even with the reduced presence, they "will continue to have a counterterrorism platform in Iraq to support partner forces with air power and intelligence".

[39] On 15 February, two people were killed and an additional 13 were injured (including an American service member) following a rocket attack on the U.S.-led coalition's base in Erbil by a suspected Iranian-backed militia.

[14][39] On 23 March, the Iraqi government formally requested a resumption of bilateral security dialogue with the U.S., taking place in April.

[41] After the third round of "strategic dialogue" concluded on 7 April, the U.S.-led coalition confirmed it would continue training and advising the Iraqi military while withdrawing combat forces from the country, citing "increasing capacity of the ISF", with a timetable forthcoming.

McKenzie also cited the continued threat Iran-backed militias posed to the coalition and affirmed his belief that ousting U.S. forces and their allies from the region was a foreign policy goal of Iran.

[3] On 26 July 2021, during Iraqi Prime Minister Mustafa Al-Kadhimi's visit to the White House during the fourth and final round of "strategic dialogue", U.S. president Joe Biden announced that the American combat mission in Iraq would conclude by the end of the year and that the remaining U.S. troops in the country would shift to an advisory role, "to be available to continue to train, to assist, to help, and to deal with ISIS".

[1] CENTCOM commander Gen. "Frank" McKenzie confirmed that U.S. troops would remain in Iraq to assist Iraqi security forces, including providing air support and military aid.