US President Donald Trump has dismissed the option of diplomatic negotiations with North Korea, declaring that "talking is not the answer" just a day after Pyongyang fired a ballistic missile over Japan, drawing international condemnation.

Key points: US senator slams Donald Trump's tweet as "most irresponsible of his presidency"

US senator slams Donald Trump's tweet as "most irresponsible of his presidency" North Korea promises more missiles, particularly in the Pacific around Guam

North Korea promises more missiles, particularly in the Pacific around Guam Malcolm Turnbull says initiating a war would be "suicide" for Kim Jong-un

Malcolm Turnbull says initiating a war would be "suicide" for Kim Jong-un Mr Trump is referring pre-2009 to food, energy assistance by "extortion money"

"The US has been talking to North Korea, and paying them extortion money, for 25 years. Talking is not the answer!", Mr Trump tweeted, renewing his tough rhetoric toward Pyongyang.

Mr Trump's latest comment appeared to undercut his own secretaries of defence and state, who have emphasised finding a diplomatic solution to North Korea's nuclear ambitions, and Pentagon chief Jim Mattis was quick to respond that diplomacy was always on the table.

"We are never out of diplomatic solutions," Mr Mattis said before a meeting with his South Korean counterpart at the Pentagon.

"We continue to work together, and the minister and I share a responsibility to provide for the protection of our nations, our populations and our interests."

Russian Foreign Minister Sergei Lavrov spoke by telephone with US Secretary of State Rex Tillerson and urged the US to refrain from any military action on the Korean peninsula that would be "fraught with unpredictable consequences", Russia's Foreign Ministry said.

North Korea has said the latest launch of an intermediate-range ballistic missile (IRBM) was to counter US and South Korean military drills and was a first step in military action in the Pacific to "contain" the US island territory of Guam.

Mr Trump, who has vowed not to let North Korea develop nuclear missiles that can hit the United States, said in a statement on Tuesday that "all options are on the table" to respond.

On Wednesday, the United Nations condemned North Korea's firing of a missile over Japan as "outrageous" while demanding that the isolated country halt its weapons program.

The US-drafted statement, which did not threaten new sanctions on North Korea, urged all nations to implement UN sanctions and said it was of "vital importance" that Pyongyang take immediate, concrete actions to reduce tensions.

'Million of lives at stake — not a game'

Sorry, this video has expired North Korea condemned by UN Security Council

Prime Minister Malcolm Turnbull told Channel Nine that North Korean leader Kim Jong-un would be signing a "suicide note" if he initiated a war.

"If the leader of North Korea continues down this provocative track the risk of war gets greater all the time," he said.

"The reality, however, is that if he starts a war, he'll lose instantly, so it would in effect be a suicide note on his part."

Mr Turnbull said that China has the ability to "put the screws on North Korea economically".

North Korea this month threatened to fire four missiles into the sea near Guam, home to a major US military presence, after Mr Trump said the North would face "fire and fury" if it threatened the United States.

The latest tweet by the US President drew criticism from Congressmen in Washington.

"Bar is high, but this is perhaps the most dangerous, irresponsible tweet of his entire Presidency," Senator Chris Murphy tweeted.

"Millions of lives at stake — not a game."

On Wednesday, Mr Kim ordered the launch to be conducted for the first time from its capital, Pyongyang, and said more exercises with the Pacific as the target were needed, the KCNA news agency said.

"The current ballistic rocket launching drill like a real war is the first step of the military operation of the KPA [Korean People's Army] in the Pacific and a meaningful prelude to containing Guam," KCNA quoted Mr Kim as saying.

North Korean 'extortion money'?

North Korean President Kim Jong-un watching a ballistic missile launch. ( KCNA )

Mr Trump's mention of "extortion money" payments to North Korea appeared to be a reference to previous US aid to the country.

A US Congressional Research Service report said between 1995 and 2008, the United States provided North Korea with more than $US1.3 billion ($1.64 billion) in assistance.

Slightly more than 50 per cent was for food and about 40 per cent for energy assistance — the assistance was part of a nuclear deal that North Korea later violated.

Since early 2009, the United States has provided virtually no aid to North Korea, though periodically there have been discussions about resuming large-scale food aid.

Sorry, this video has expired Japan's PM Shinzo Abe provides a brief statement on latest North Korea missile launch

Reuters/ABC