We are going to remain committed to the government, remain committed diplomatically.
"The president has judged that a conditions-based approach, which has been the approach for the last two decades, is a recipe to stay in Afghanistan forever", the official said.
The timeline for Biden's withdrawal will break the May 1 deadline set by the Trump administration in an agreement with the Taliban by several months. "After 20 years, thousands of lives lost, and trillions of dollars spent, we are finally bringing home our troops from Afghanistan", Khanna said in a statement.
The delay will give USA commanders time to conduct an orderly withdrawal, instead of a rush to depart by next month, the senior official said.
The deal signed in February a year ago said the USA and its North Atlantic Treaty Organisation allies would withdraw all troops in 14 months if the Taliban upheld its promises, including not allowing al-Qaeda or other militants to operate in areas it controlled and proceeding with national peace talks.
According to the official, Biden was adamant that a hasty, ill-coordinated withdrawal that puts at risk United States forces and those of its allies and operational partners is not a viable option.
"We have communicated to the Taliban in no uncertain terms, that if they do conduct attacks against USA or allied forces as we carry out this drawdown ... that we will hit back hard and we will hold them accountable for that", the official said.
NATO, US vow support for Ukraine, warn Russia on troops
Ukraine has said Russian Federation has accumulated 41,000 troops at its border with eastern Ukraine and 42,000 more in Crimea. Kuleba appealed for further economic sanctions against Moscow and more military help to Kyiv.
A U.S. official said on Tuesday that President Joe Biden had reached the conclusion to end Washington's two-decade involvement in Afghanistan by late this year. USA officials have also blamed the Taliban for failing to live up to commitments to reduce violence and some have warned about persistent Taliban links to al Qaeda.
The U.S. will help the roughly 7,000 North Atlantic Treaty Organisation troops in Afghanistan pull out of the country under a principle of "in together, out together", the official said.
U.S. Secretary of State Antony Blinken and U.S. Defense Secretary Lloyd Austin are expected to discuss the decision with North Atlantic Treaty Organisation allies in Brussels on Wednesday, sources said.
On Tuesday, the administration official warned that there would be consequences for the Taliban if it attacked USA or allied forces during the drawdown.
Sources told CNN that Biden had been weighing the decision for months and indicated he did not want to keep troops in Afghanistan much longer past May 1. "We will remain in lockstep with them as we undergo this operation", said the official.
Democratic Senator Jack Reed, chairman of Senate Armed Services, called it a very hard decision for Biden. "We believe we certainly can complete that by September, and the question of how long before September depends on conditions as the drawdown unfolds".
United States intelligence also released a report that found that Afghanistan's government would "struggle" to stand its ground against the "confident" Taliban.