North Korea’s nuclear program is making the world more nervous

North Korea said on Tuesday it successfully test-launched an intercontinental ballistic missile (ICBM) for the first time.

According to experts, the missile flew a distance that could allow a weapon to hit the U.S. state of Alaska.

The launch came days before leaders from the Group of 20 nations were due to discuss steps to rein in North Korea's weapons program, which it has pursued in defiance of U.N. Security Council sanctions.

The launch, which North Korea's state media said was ordered and supervised by leader Kim Jong Un, sent the rocket 933 km (580 miles) reaching an altitude of 2,802 km over a flight time of 39 minutes.

North Korea has said it wants to develop a missile mounted with a nuclear warhead capable of striking the U.S. mainland.

To do that it would need an ICBM with a range of 8,000 km (4,800 miles) or more, a warhead small enough to be mounted on it and technology to ensure its stable re-entry into the atmosphere.

Some analysts said the flight details on Tuesday suggested the new missile had a range of more than 8,000 km, underscoring major advances in its program. Other analysts said they believed its range was not so far.

Officials from South Korea, Japan and the United States said the missile landed in the sea in Japan's Exclusive Economic Zone after being launched on a high trajectory from near an airfield northwest of the North's capital, Pyongyang.

"The test launch was conducted at the sharpest angle possible and did not have any negative effect on neighboring countries," North Korea's state media said in a statement. The North said its missiles were now capable of striking anywhere in the world.

"It appears the test was successful. If launched on a standard angle, the missile could have a range of more than 8,000 km," said Kim Dong-yub, a military expert at Kyungnam University's Institute of Far Eastern Studies in Seoul.

"But we have to see more details of the new missile to determine if North Korea has acquired ICBM technology."

U.S. President Donald Trump wrote on Twitter: "North Korea has just launched another missile. Does this guy have anything better to do with his life?" in an apparent reference to North Korean leader Kim Jong Un.

"Hard to believe South Korea and Japan will put up with this much longer. Perhaps China will put a heavy move on North Korea and end this nonsense once and for all!", Trump said in a series of tweets.

Stock markets in both South Korea and Japan fell, with the Kospi ending down 0.6% and Japan's Nikkei share average ending down 0.1%.