NATO has defended the use of economic sanctions against Russia, suggesting they could prevent Moscow from invading other countries.
After annexing Crimea from Ukraine in 2014, a move that has not been recognized internationally, Russia said it would not return the region. In response, the United States and European Union have imposed economic sanctions on Russian companies and individuals.
Speaking in Austria on Tuesday, Russian President Vladimir Putin claimed the measures were counterproductive as they had proved harmful to all parties involved.
But NATO Secretary-General Jens Stoltenberg told CNBC's Willem Marx on Friday that the sanctions were necessary to thwart Russian bullying.
"I think it is at least obvious that if we hadn't done anything it would have lowered the threshold for Russia to do similar things against other countries," Stoltenberg said at the close of a two-day meeting of defense ministers in Brussels.
"Russia has violated the sovereignty and territorial integrity of neighbor Ukraine and has continued to destabilize eastern Ukraine. It has to have consequences, it has to have a cost," he added.
Ukrainian, Russian, German and French foreign ministers are due to meet in Berlin on Monday to discuss the conflict in eastern Ukraine.
While the total defense spending by NATO allies has risen for four consecutive years, it received harsh criticism from President Donald Trump in 2017. Trump highlighted the outsized contribution from the United States while noting that Germany in particular wasn't hitting the 2 percent of GDP target.
NATO has now unveiled higher expenditure estimates for 2018, with spending among European members, Canada and Turkey forecast to rise by more than 3.8 percent this year.
Stoltenberg told CNBC on Friday that he had personally thanked Trump for helping to force the bigger budgets.
"I met President Trump in the White House and thanked him for his leadership on defense spending because that message has helped me as I travel around NATO capitals," he added.
Stoltenberg said that a "corner had been turned" on the financial commitments to NATO and that in turn had helped to place more U.S. troops in Europe.