North Korea on Friday launched an intercontinental ballistic missile for the second time in a month, the Pentagon said, a day after US Congress voted to impose new tougher sanctions against Russia, Iran and Pyongyang.

The unusual late-night test launch prompted the heads of the US and South Korean militaries to discuss "military response options", the Pentagon said.

It was North Korea's 12th missile test this year and second intercontinental ballistic missile (ICBM) in less than a month.

"The US Department of Defence detected and tracked a single North Korea missile launch today at about 10:41 AM (New York time)," Pentagon Spokesman Capt Jeff Davis said.

"We assess that this missile was an intercontinental ballistic missile (ICBM), as had been expected. The missile was launched from Mupyong-ni and travelled about 1,000 km before splashing down in the Sea of Japan.

"We are working with our interagency partners on a more detailed assessment," Davis said.

The North American Aerospace Defence Command (NORAD) determined the missile launch from North Korea did not pose a threat to North America, he said.

"Our commitment to the defence of our allies, including the Republic of Korea and Japan, in the face of these threats, remains ironclad. We remain prepared to defend ourselves and our allies from any attack or provocation," Davis said.

Speaker of the US House of Representatives Congressman Paul Ryan said: "North Korea is a global menace and its pursuit of nuclear-capable intercontinental ballistic missiles poses clear and immediate danger to our national security. We take this threat very seriously.

"That's why, earlier this week, a bipartisan majority of the House voted to sanction North Korea. These expansive sanctions directly target Pyongyang's ability to threaten the United States and our allies. The Kim (Jong-Un) regime needs to pay for its actions," Ryan said.

Harry J Kazianis, director of Defence Studies from the Centre for the National Interest, a recognised expert on North Korea, said the latest test should not come as a surprise.

"North Korea is slowly morphing into a nuclear and missile power right before our very eyes. North Korea will continue to test over and over again its missile technology and nuclear weapons in the months and years to come in order to develop the most lethal systems it can.

"And you can bet every time they do tensions will continue to rise. This is what makes the situation on the Korean Peninsula as dangerous as it is," he said.

A day earlier, Commander of US Pacific Command Admiral Harry Harris said North Korea is "a clear and present danger" to global peace and stability.

North Korean leader Kim Jong-Un's regime is not only a threat to South Korea, Japan and the US, but to China, Russia and US allies in the Pacific and Indian Oceans, he said.

"(North Korea is) a threat to the entire world because North Korea's missiles point in every direction. It's the reason why we call for all nations to implement far stronger economic sanctions against Pyongyang," Harris said at an event at the Japanese Embassy in Washington.

The provocative North Korea ICBM test comes in less than 24 hours of the Senate passing 98-2 a bill to impose tough sanctions on Russia, North Korea and Iran.

"Kim Jong-Un must end his dangerous pursuit of a nuclear weapon or face total economic isolation. The sanctions will limit access to foreign currency and the ability to conduct trade, severely weakening the North Korean economy," said Senator Dianne Feinstein.

"It also gives us the ability to work with the UN to impose harsh penalties against any foreign entity that violates or helps North Korea circumvent these sanctions," she said.

In the past a few days, the Trump administration has ramped up its pressure on China to use its leverage on North Korea from going ahead with its missile tests.

"We expected China to exert its very considerable, economic, political and diplomatic pressure on North Korea.

The president has said he is not satisfied with the results," Sebastian Gorka, a top presidential adviser told PBS News early this week.

"That's why the president on the fringes of the G20 sat down with the heads of state of both South Korea and Japan to take the North Korean issue back to the UN Security Council.

And why the president, additionally, at the end of the G20 had a conversation with (Chinese President) Xi Jinping to tell him exactly what he thought about what China needs to do right," he said.

"Right now we're going to maintain our policy of peaceful pressure with regards to North Korea, hoping that China can step up to the plate, while the president takes no options off the table," Gorka said.

Following the North Korean ICBM launch, Chairman of the Joint Chiefs of Staff, General Joseph Dunford and Commander of US Pacific Command Admiral Harry Harris called South Korean Joint Chiefs of Staff Chairman General Lee Sun Jin.

"During the call, Dunford and Harris expressed the ironclad commitment to the US-Republic of Korea alliance. The three leaders also discussed military response options. Harris joined Dunford in his Pentagon office to make the phone call," the Joint Chief of Staff Chairman's spokesman Navy Capt Greg Hicks said.

Senator Ben Cardin, Ranking Member of the Senate Foreign Relations Committee, said the ICBM test is further evidence of Pyongyang's determination to develop nuclear weapons and ballistic missiles.

"The US stands by our allies in Seoul and Tokyo, and there should be no question of our ironclad alliance commitments to safeguard our common security and the people of South Korea and Japan," he said.

In a statement, he said that the UN Security Council will also take additional measures to address Pyongyang's wanton disregard for the will of the international community, and the threat that its nuclear and missile programs pose to regional peace and stability.

"This latest test also makes clear that the president's approach to North Korea is not working, and I call on the president and his national security team to rethink how the US can best combine pressure, sanctions, our alliances and our military might with agile and forward-leaning diplomacy to seek to effectively address North Korea's malign ambitions," Cardin added.