NATO Secretary-General Jens Stoltenberg warned in an interview with the Financial Times that a UK vote to leave the EU could throw the turnaround into jeopardy, Censor.NET reports.
"The forecast for 2016, based on figures from allied nations, indicates that 2016 will be the first year with increased defense spending among European allies for the first time in many, many years," Mr Stoltenberg said.
"We are faced with uncertainty, we are faced with more threats, more security challenges than in a generation, and we need unity, we need strength, we need stability," he added
"The UK is the largest European provider of defense capabilities in NATO, [it has] the biggest defense spending, it has the biggest defense investments … second only to the United States in the whole alliance … a strong UK in a strong Europe is important for unity and stability," Mr Stoltenberg said.
The EU is becoming increasingly important in almost all the challenges NATO has to deal with, Mr Stoltenberg added. The UK is "key" in developing the relationship between the two, he said.
"NATO and the European Union are working in tandem. For the UK [remaining] is a good position to be in, to be able to sit at both the NATO table and the EU table, since both organisations are so important to how we are responding to the instability we are faced with, both to the east and to the south."
Last year, NATO's European allies spent $253 bn on defense compared with a US spend of $618 bn. According to the 2 per cent guideline, European countries should be spending an additional $100 bn annually on their militaries. The current spend is equivalent to around 1.43 per cent of gross domestic product.
The Baltic states which border Russia have made the biggest changes. Latvia's budget will rise nearly 60 per cent this year. Lithuania will see a 35 per cent increase and Estonia 9 per cent. Poland, eastern Europe's main military power, is also raising defense expenditure 9 per cent.
The UK's military budget is also rising. The government has pledged to increase spending in order to maintain the 2 per cent of GDP alliance target.
At NATO's 2014 summit in Wales, amid alarm over Russia's invasion of Crimea and Moscow's growing military actions, allies pledged to freeze all further cuts in their defense budgets and work towards hitting NATO benchmarks for spending over the next 10 years. NATO allies were supposed to spend 2 per cent of their annual GDP on defense.
"We still have a long way to go but the picture's better than it was before and I'm inspired by the fact that one year after the commitment in Wales we have been able to stop the cuts in Europe. Now it looks like, into the second year, we will have the first real increase in total European defense spending," said Mr Stoltenberg.
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