US-Taliban deal overshadowed by Afghan political chaos
The US is reducing its military presence in the country from 13,000 to 8,600, as stipulated by the February agreement.
The 18-month withdrawal process demands only that the Taliban honour its commitment to "prevent any group or individual, including Al-Qaeda" from using the country "to threaten the security of the US and its allies".
"In accordance with the US-Islamic Republic of Afghanistan Joint Declaration and the US-Taliban Agreement, US Forces Afghanistan (USFOR-A) has begun its conditions-based reduction of forces to 8,600 over 135 days," US Forces Afghanistan spokesman Col. Sonny Leggett said.
Eight thousand US soldiers are currently involved in training and advising Afghanistan's National Security Forces, while 5,000 more troops are assisting the local army in anti-terror operations and ad-hoc military support.
Yet, as hundreds of troops left in Washington's latest effort to end its longest war, Afghanistan's rival leaders held parallel inauguration ceremonies on Monday, casting a large shadow of doubt on the deal's long-term viability.
The fierce dispute pitted Afghan President Ashraf Ghani, who was announced the winner of last September’s election, against his opponent Abdullah Abdullah, who charged fraud in the same contest.
Ghani's ceremony was disrupted by the sound of two rockets hitting the edge of the presidential palace compound. There was no word of any casualties, and he continued his speech.
Abdullah, backed by the country's election complaints commission, sent his vice presidents to occupy the official offices on Monday, ahead of Ghani’s plan to send his juniors to their offices on Tuesday.
US Secretary of State Mike Pompeo condemned the establishment of a parallel government in Kabul, warning against "any use of forces to resolve political differences".
The two candidates - particularly Abdullah - are buttressed by powerful warlords in command large militias.
While Ghani has started to build a negotiating team, Afghan analysts fear that armed conflict looms as a possibility, if the seat of power remains contested.
As the US and foreign powers sent representatives to his inauguration to support his claim to presidency, Ghani on Monday pledged to release around 5,000 Taliban prisoners, another key outcome of the US-Taliban deal.
Read more: Scores killed as suspected IS-linked militants storm Kabul ceremony attended by head of government
The move was lauded by Pompeo, who said in a statement on Monday: "We also welcome President Ghani's announcement that he will issue a decree March 10 on Taliban prisoner release."
According to Taliban officials who spoke to AP on condition of anonymity, biometric identifications of Taliban prisoners were underway late on Monday, hinting at a mass release.
On the weekend, Taliban spokesman Zabihullah Mujahed said the insurgent group was committed to their agreement with the United States and called on Washington to do its part to make sure their prisoners were freed.
The Islamic State group claimed responsibility for the rocket attack that took place during Ghani's inauguration ceremony.
IS also claimed a brutal attack last week on a gathering of minority Shia Muslims that killed 32 and injured scores more.
The US in reaching its deal with the Taliban said they expected the Taliban, which has been battling Afghanistan's IS affiliate, to further aid in the effort to defeat IS.
Agencies contributed to this report.