Thousands of American military personnel currently stationed in Germany will return to the United States.
Nearly 12,000 military personnel will leave the country, following a decision made by President Donald Trump last month.
Out of 11,900 US service members, nearly 5,600 will be redeployed to countries within NATO, such as Belgium and Italy, with approximately 6,400 returning to the United States.
Many of these units will begin conducting rotational deployments back to Europe to address tensions with Russia, US Defense Secretary Mark Esper has said, with changes beginning "in a matter of weeks".
The US says the changes will reduce the number of American military personnel in Germany from around 36,000 to 24,000.
Meanwhile, the 2,500 airmen and women based at RAF Mildenhall in the UK, who are responsible for aerial refuelling and special operations and had been scheduled to re-base to Germany, will remain in the United Kingdom.
The US Defense Secretary said these changes will "achieve the core principles of enhancing US and NATO deterrence of Russia, strengthening NATO, reassuring Allies, and improving US strategic flexibility and EUCOM operational flexibility".
US President Donald Trump confirmed last month his intention to cut the number of US troops in Germany, criticising the US ally for failing to meet NATO's defence spending target and accusing the country of taking advantage of America on trade.
Announcing the cut, Mr Trump criticised Germany for failing to pay enough for its own defence, calling the country "delinquent" in its payments to NATO.
"We’re protecting Germany and they’re delinquent. That doesn’t make sense," he said in June.
The President has long-called for NATO nations to reach the alliance's target of spending 2% of GDP on defence - regularly singling out Germany as a major offender.
Germany says it hopes to hit 2% by 2031 - seven years later than the original NATO goal.
Watch: President Trump confirmed US troops would be leaving Germany last month.
Mr Esper defended Donald Trump, saying: "When you step back and look at what’s happened, what you will see is we are still retaining a little more than 24,000 troops in Germany, which is still a lot, I think, still more than any country in Europe."
He went on to say the area likely to be most affected will be Stuttgart, but added he had a "good conversation" with the German Defence Minister.
The premiers of four German states which host American troops have appealed to members of the US Congress to block Mr Trump’s withdrawal, which has been criticised as politically, rather than strategically, driven.
Mr Esper had already been carrying out a review of US forces globally when Mr Trump’s long-running dispute with Germany peaked.
Chair of the UK Defence Select Committee, Tobias Ellwood MP, said the White House should "reconsider" the move.
He told the BFBS Sitrep podcast: "It's in the United States' interests to have a strong Western Europe, it's in the West's interest for us to collectively work together.
"The reason why China is able to advance its agenda so easily it's because the West has become weak and there's no collective resolve."
The US military has five garrisons in Germany and two air bases.
In February, the UK handed over its final military headquarters in Germany - marking the complete withdrawal of 20,000 troops from the country.
Despite the departure of major field and combat units, the UK maintains a training presence there.
Cover image: US Air Force.