Facing tight budgets and a shrinking military, the United States said on Thursday it was ending operations at an air base in Britain and handing it and 14 other sites in Europe back to their home governments.
In the biggest move, the Pentagon said it would leave RAF Mildenhall northeast of London, home to tanker, reconnaissance and special operations aircraft, and withdraw 3,200 military personnel and their families.
The changes, including new construction at some bases, were expected to cost $1.4 billion but result in savings of $500 million a year once fully implemented.
Several facilities in Germany would be closed, but overall U.S. troop numbers there were expected to rise a few hundred. Some 500 U.S. personnel would be withdrawn from Lajes Field in the Azores, reducing U.S. troop numbers in Portugal. About 300 troops would be shifted from Germany to Italy.
Assistant Defense Secretary Derek Chollet said the changes in half a dozen European countries would reduce support infrastructure but would not affect the U.S. military's operational capacity in the region.
"These ... adjustments do not diminish our ability to meet our commitments to allies and partners," Chollet told a Pentagon briefing. "In fact, these decisions will produce savings that will enable us to maintain a robust force presence in Europe."
The reductions at RAF Mildenhall would be partially offset by a Pentagon decision to add 1,200 personnel and two squadrons of F-35 Joint Strike Fighters at nearby RAF Lakenheath, home to the U.S. 48th Fighter Wing. The net loss of U.S. troops in Britain would be about 2,000.
British Defense Secretary Michael Fallon voiced disappointment at the loss of U.S. forces from Mildenhall and two other bases, but said in a statement to Parliament that the advance notice would help mitigate the local impact. The Mildenhall withdrawal is not likely to begin until 2019.
Fallon said the decision to base F-35s at Lakenheath "paves the way for continued close collaboration between our respective forces."
The Pentagon, under orders to reduce projected spending by nearly $1 trillion over a decade, has repeatedly asked Congress to close some facilities in the United States, where excess capacity is thought to be around 20 percent.
Lawmakers have resisted closures, with some telling defense officials to cut excess facilities in Europe first. The United States has more than 64,000 troops stationed in Europe, most in Germany, Italy and Britain.
John Conger, the Pentagon's top official for installations management, said the consolidation of U.S. bases in Europe, a process that has been under discussion with Congress and allies for two years, could help the department gain support to move ahead with closing unneeded facilities in the United States.
The cost-cutting comes amid heightened tensions between Russia and NATO after Moscow's annexation of the Ukraine's Crimean region and its support for pro-Russian militants opposed to the Kiev government.
Last week, Lieutenant General Ben Hodges, commander of U.S. Army troops in Europe, underscored the need to retain the current force structure in Europe until the security picture clarifies.