US troops are preparing for Defender Europe 2020 Exercise (Picture: PA).
The United Kingdom is expected to take part in a military exercise with the United States in 2020.
The US military said it is preparing for the exercise in Europe next year.
It will involve 20,000 US soldiers, making it one of the largest training deployments across the Atlantic in more than 25 years.
US European Command said the Defender Europe 20 exercise will run from April to May 2020.
The exercise will support NATO objectives "to build readiness within the alliance and deter potential adversaries".
Eighteen countries are expected to take part in exercises across 10 countries, including Germany, Poland, Latvia, Lithuania, Estonia and Georgia.
It will also involve 9,000 more Americans already stationed in Europe and 8,000 European troops.
The US military said the exercise confirms America's "commitment to NATO and the defence of Europe remains ironclad".
President Donald Trump has worried many NATO members with comments that the transatlantic alliance is "obsolete".