European nations could face a trillion-dollar rearmament bill in the face of a looming Russian threat and an imminent US defense review that could see Washington dramatically draw down forces on the continent, according to a report released on September 3.

The 106-page report, by the London-based International Institute for Strategic Studies(IISS), points to gaps across the board: in production, intelligence, and military hardware such as long-range missiles orair and missile defense.

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Chief among the reasons for this greater urgency are Russias military threat and uncertainty over the United States commitment to defending European allies, it says.

While strategic assessments vary across European nations about how quickly Russian forces could constitute a direct threat to NATO Europe, their time frames generally range between two and five years.

Meanwhile, the Pentagons Global Force Posture Review is expected to be published this month and lay out a shift in military resources from Europe to Asia/Pacific.

Some NATO officials believe a US troops reduction of up to 30 percent could be possible, says the report, entitled Progress and Shortfalls in Europes Defense: An Assessment.

Rising Military Budgets

European leaders have madeplansthis year to respond to these challenges. In March, a European Union summit pledged to spend billions on defense amid what EU Commission President Ursula von der Leyen called a watershed moment for Europe.