The United States is "done talking about North Korea", US ambassador to the United Nations Nikki Haley has warned, after North Korea fired its second long-range missile this month.

Key points: Nikki Haley says North Korea is not just a US problem

Nikki Haley says North Korea is not just a US problem North fired intercontinental ballistic missile on Friday

North fired intercontinental ballistic missile on Friday US flies bombers over Korean Peninsula

"Done talking about North Korea. China is aware they must act," Ms Haley wrote on Twitter.

"Japan and South Korea must increase pressure. Not only a US problem. It will require an international solution."

She then posted a link to photos of the United States, Japan and South Korea conducting bomber jet drills over the Korean Peninsula on Sunday.

The United States flew two supersonic B-1B bombers as a show of force after Pyongyang fired an intercontinental ballistic missile (ICBM) on Friday.

Sorry, this video has expired US bombers fly over Korean Peninsula in response to Pyongyang missile test.

Ms Haley later said in a statement that any new UN Security Council resolution "that does not significantly increase the international pressure on North Korea is of no value".

"China must decide whether it is finally willing to take this vital step. The time for talk is over," she said.

Ms Haley was echoing the sentiments of US President Donald Trump, who took to Twitter to put pressure on China, North Korea's only ally.

"I am very disappointed in China," he tweeted.

"Our foolish past leaders have allowed them to make hundreds of billions of dollars a year in trade, yet they do NOTHING for us with North Korea, just talk. We will no longer allow this to continue. China could easily solve this problem!"

The Chinese mission to the United Nations did not immediately respond to a request for comment.

Nikki Haley is calling for Japan and South Korea to increase pressure on Pyongyang. ( Reuters: Mike Segar )

Missile test 'put all of the US within range'

Over the weekend North Korea fired an inter-continental ballistic missile which landed in the Sea of Japan.

Analysts who watched the launch, from a mobile launcher in a forested area, concluded that the weapon could hit major US cities including Los Angeles and Chicago.

Shea Cotton from the James Martin Centre for Non-proliferation Studies in California said the launch, late on Friday night local time, was the second test of the ICBM system.

"Our estimates from the first one had the missile going about 6,700 kilometres, which put Alaska within range," she told AM on Saturday.

"Our estimates with this one [are] that if it was fired within full range ... this would go about 10,000 to 11,000 kilometres and at that point they've basically put all of the United States within range".

The United States has been in talks with North Korean ally China on a draft UN Security Council resolution to impose stronger sanctions on North Korea.

Two B-1B Lancer bombers are escorted by a Japanese fighter jet over the Korean Peninsula. ( Reuters: US Air Force )

Ms Haley gave China a draft text after the first ICBM test.

She said last Tuesday that the United States had been making progress with China.

Some diplomats had expected the United States, Japan and South Korea to ask for the 15-member UN Security Council to meet on Monday over the test, but no such request has yet been made.

Such a meeting would set the stage for a likely showdown between the United States and Russia.

Trump, Abe agree more action on North Korea required

Japanese Prime Minister Shinzo Abe spoke with Mr Trump on Monday and agreed on the need for more action on North Korea.

A White House statement after the phone call said the two leaders "agreed that North Korea poses a grave and growing direct threat to the United States, Japan, the Republic of Korea, and other countries near and far".

It said Mr Trump "reaffirmed our ironclad commitment" to defend Japan and South Korea from any attack, "using the full range of United States capabilities".

Japan's Chief Cabinet Secretary Yoshihide Suga said the talk between Mr Abe and Mr Trump lasted for about 50 minutes.

"The role that China can play is extremely important," Mr Suga told a news conference.

"Japan intends to call on those countries involved — including the UN, the United States and South Korea to start, but also China and Russia — to take on additional duties and actions to increase pressure," he added, declining to give details about what those steps might be.

Disagreement over type of missile tested

Diplomats say China and Russia only view a long-range missile test or nuclear weapon test as a trigger for further possible UN Security Council sanctions.

The Pentagon and South Korean military believe Friday's test was a long-range ICBM, but a Russian Defence Ministry official said Moscow's data indicated it was only a medium-range missile.

South Korean media reported the missile launched by North Korea was a long-range ICBM. ( AP: Ahn Young-joon )

North Korea has been under UN sanctions since 2006 over its ballistic missile and nuclear programs, and the Security Council has ratcheted up the measures in response to five nuclear weapons tests and the recent missile launches.

Ms Haley has said options to strengthen UN sanctions include restricting the flow of oil to North Korea's military and weapons programs, increasing air and maritime restrictions, and imposing sanctions on senior officials.

Traditionally, the United States and China have negotiated sanctions on North Korea before formally involving other Security Council members.

Reuters