Donald Trump has frequently spoken about the need for NATO allies to increase the amount they spend on defense.

NATO Secretary General Mark Rutte said members have to boost spending. If not Europeans should "get out your Russian language courses or go to New Zealand," he said. NATO Secretary General Mark Rutte told members of the security alliance to boost defense spending or prepare to learn Russian.

NATO secretary-general rained fire on EU members of the U.S.-led bloc over defence spending on Monday. Mark Rutte told an European committee that members need to increase their defence spending or learn Russian as they could face an attack anytime after 4-5 years.