NEW YORK (AFP) - United States President Donald Trump on Sunday (Sept 23) flew to New York ahead of this week's gathering of world leaders at the United Nations, where he met Japan's Prime Minister Shinzo Abe in the evening.

"Going to New York. Will be with Prime Minister Abe of Japan tonight, talking Military and Trade. We have done much to help Japan, would like to see more of a reciprocal relationship. It will all work out!" he tweeted before his helicopter landed in Wall Street at around 5.45pm local time.

Following dinner with Mr Trump at the President's New York tower, Mr Abe told reporters that the pair discussed North Korea and its abduction of Japanese citizens, along with US-Japan and international trade, "in a warm atmosphere as usual".

"On the North Korean issue, we agreed to further boost the momentum created at the historic US-North Korea summit in June and cooperate closely and firmly in realising the denuclearisation of the Korean peninsula," Mr Abe said.

North Korea and Iran are set to dominate the UN General Assembly, where Mr Trump will be in the spotlight as he continues to upend global diplomacy.

After warming up to North Korean leader Kim Jong Un and ditching the Iran nuclear deal, the unpredictable Trump takes the podium on Tuesday to face foes and increasingly uneasy allies.

On Wednesday, he will, for the first time, chair a Security Council meeting on non-proliferation and weapons of mass destruction that will focus heavily on Iran - likely triggering a clash with other big powers.