"We did not go to Afghanistan to nation build," the president said in a speech on Thursday, adding: "Afghan leaders have to come together and drive toward a future."
The US leader stressed that "speed is safety," with the withdrawal of US military operations coming as the Taliban make rapid advances in significant swaths of the country.
It comes as Prime Minister Boris Johnson said that most of the remaining British troops have left Afghanistan after 20 years, but said the UK would continue to support the government of President Ashraf Ghani with more than £100 million in development aid and £58 million for the Afghan security forces.
Reaffirming the justification for withdrawing from the country, the Biden administration has repeatedly sought to frame ending the conflict as a decision made after concluding it’s an "unwinnable war" and one that "does not have a military solution."
"How many more, how many more thousands of American daughters and sons are you willing to risk?" President Biden said to those calling for the US to extend the military operation.
"I will not send another generation of Americans to war in Afghanistan, with no reasonable expectation of achieving a different outcome."
The president said he didn’t trust the Taliban but trusted the capacity of the Afghan military to defend the government.
Before his speech, White House press secretary Jen Psaki said Biden administration officials always anticipated an "uptick" in violence and greater turmoil in Afghanistan as the withdrawal of US troops continued.
She added that prolonging military involvement, considering former President Donald Trump had already agreed to withdraw from Afghanistan by May 2021, would have led to an escalation of attacks on American troops.
"The question fundamentally facing him was after 20 years was he going to commit more American troops to a civil war in Afghanistan," Ms Psaki said.