"Back in 2013, 3 NATO Allies spent at least 2% of GDP on defense. This year, we expect 8 Allies to spend 2%," Stoltenberg said as quoted by NATO spokeswoman Oana Lungescu in a tweet, without mentioning the countries that were likely to meet the target.
Stoltenberg made this remark during his address to the NATO Parliamentary Assembly Spring Session in Poland earlier in the day.
Responding to the establishment of a US base in Poland, Russia said it was ready to react to NATO's infrastructure expansion.
During the summit in Wales in 2014, NATO member states reaffirmed their commitment to allocate 2 percent of GDP for defense spending. Moreover, those states, which did not meet the 2-percent target, pledged to reach it within a decade.
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In 2017, total defense expenditure by NATO members grew to 2.42 percent of their GDP from 2.4 percent in 2016. This number is still less than 3.57 percent of GDP spent on defense by the United States. US President Donald Trump has repeatedly criticized Washington's European allies for falling short of meeting the 2-percent target and called on them to increase their military spending.
NATO has been significantly expanding its presence in Eastern Europe after the outburst of the Ukrainian crisis in 2014 using alleged Russian interference in the Ukrainian internal activities as a pretext.
Moscow has many times asserted its protests against the NATO military buildup stating that this move will undermine regional balance and result in a new arms race.