The US will reduce the number of its troops in Iraq and Afghanistan by mid-January 2021, the country's Acting Defense Secretary has said.
Christopher Miller announced on Wednesday that the number of troops in Afghanistan will fall from around 4,500 to 2,500 and from 3,000 to 2,500 in Iraq.
"I am formally announcing that we will implement President Trump's orders to continue our repositioning of forces from those two countries," Mr Miller said.
"This is consistent with our established plans and strategic objectives, supported by the American people, and does not equate to a change in policy or objectives," he added.
The plan will mean an acceleration in the US withdrawal from the two countries during President Donald Trump's final days in office.
Mr Miller said he had spoken to Afghan and Iraqi officials, as well as NATO Secretary General Jens Stoltenberg.
Mr Stoltenberg warned earlier in the week that the alliance could pay a heavy price for withdrawing troops from Afghanistan "too soon".
"We now face a difficult decision," the NATO chief said.
"We have been in Afghanistan for almost 20 years, and no NATO ally wants to stay any longer than necessary.
"But at the same time, the price for leaving too soon or in an uncoordinated way could be very high."
NATO's Secretary General warned Afghanistan risked becoming "once again a platform for international terrorists to plan and organise attacks on our homelands".
Speaking at the Pentagon on Wednesday, Mr Miller added the decision is not irreversible and that the US "stands ready to ally the capabilities required to thwart" forces of terror.
Tobias Ellwood MP, chair of the UK Defence Select Committee, called the withdrawal plan a "complete mistake" and speculated the move could be a deliberate attempt to "stir things up" for Mr Trump's successor Joe Biden.
"I don't understand why Donald Trump is choosing to do this. The mission is by far not completed - both Afghanistan and Iraq," he told Forces News.
US troops have been in Afghanistan since 2001 and peace negotiations reached an important point when a US-Taliban peace agreement was signed in February.
But Afghan military and defence leaders have consistently accused the Taliban of not doing enough to reduce violent attacks on government forces.
Mr Ellwood said: "Talks in Afghanistan are at a critical stage. Why would you want to give space to the opposition, and to insurgents and extremists, to take advantage of your departure at such a fundamental time?"
"Likewise in Iraq, there is still an awful amount of danger that is presented by extremist groups."
Mr Ellwood also described the decision to deny Mr Biden access to security briefings as "deeply irresponsible".
He said he hoped the US forces will "simply take their time and delay this as much as possible, until the decision can be overturned" after Inauguration Day on 20 January.
Mr Ellwood said he understood the remaining troops will be tasked with embassy and diplomatic housing security, leaving behind broader security roles in Afghanistan and the training of local forces.
The UN's top official for refugees has warned that a collapse of the Afghan peace process would cause a "humanitarian disaster".
Filippo Grandi, UN High Commissioner for Refugees, warned that if the fighting continues, more people would be forced to flee their homes.
He said: "If this peace effort collapses then we could see a big humanitarian disaster in the country. That is for sure. I hope it won’t."
Cover image: US troops in Afghanistan (Picture: US Department of Defense).