"But this all changes that. I think it speaks to the fact they have an ongoing missile testing program and sooner or later it will be a crisis. But what happened over this weekend I think is more a dress rehearsal for a crisis," Hill said.

The North carried out the missile launch on Sunday morning local time in the first provocative act by Pyongyang since the inauguration of US President Donald Trump. The launch came after North Korean leader Kim Jong-un threatened to test-fire an intercontinental ballistic missile apparently capable of reaching the US.

Experts said the latest firing could be aimed in part at testing how the Trump administration would react to a missile launch before the regime goes ahead with a full-fledged ICBM test that Trump has pledged to prevent from happening.

On Monday, the North said the launch represented a successful test of a newly developed intermediate-range missile powered by solid fuel. Weapons experts say solid-fuel missiles pose greater threats as they require less preparation time than liquid-fueled rockets, and can be fired from mobile launchers easy to move around.

Hill said that the problem the Trump administration is that there are not enough people focused on dealing with the North Korea issue. Still, he said it's fortunate that the new administration has been working to reassure allies of the US security commitments, including Defense Secretary Jim Mattis' trip to South Korea and Japan.

In response to the missile launch, Trump held an impromptu press conference with Japanese Prime Minister Shinzo Abe and reaffirmed the commitment to defending the ally. Hill said it would have been better if Trump had mentioned South Korea as well.

Hill also called for greater cooperation with China.

"In the coming weeks and months he's going to have to really work with the Chinese. And there again he's going to have to set some priorities. Do we want a trade war with China? Do we want to really fan tensions with them? Or do we want to try to work on North Korea?" he said.

"I know it's a proposition that hasn't really had a lot of success but we know that China doesn't want North Korea to make progress here. And we ought to be able to work with them a little better than we do," he said. (Yonhap)