NATO allies excluding the United States will increase defence spending this year by 4.3 percent, alliance chief Jens Stoltenberg said Wednesday, amid pressure from President Donald Trump to spend more.

"In 2017, we foresee an even greater annual real increase of 4.3 percent. We are really shifting gears, the trend is up and we intend to keep it up," Stoltenberg told reporters on the eve of a defence ministers meeting in Brussels.