US President Donald Trump has paved the way for sanctions against foreign companies doing business with North Korea, a dramatic ratcheting up of pressure on the regime.

Tensions have risen as Pyongyang has resisted intense international pressure, and the rhetoric between Mr Trump and Kim Jong Un has also escalated. The US president on Tuesday called him a "rocket man," and Kim today described Mr Trump as "mentally deranged."

The escalating rhetoric came as even the UN Secretary General called for statesmanship to avoid "sleepwalking" into a war. South Korea, Russia and China all urged calm.

Kim Jon Un said the North would consider the "highest level of hard-line countermeasure in history" against the United States in response to Mr Trump's threat to "totally destroy" the North in his first speech to the United Nations on Tuesday.

Tightening an economic noose around the Pyongyang regime, Mr Trump said he had signed an executive order allowing sanctions against "individuals and companies that finance and facilitate trade with North Korea."

The measure could force Chinese banks or Russian importers to decide between doing business with North Korea or being blacklisted by the United States.

"Our new executive order will cut off sources of revenue that fund North Korea's efforts to develop the deadliest weapons known to humankind," Mr Trump said.

Such sanctions were previously used on Iran, with many companies deciding to scrap trade with Tehran for fear of being frozen out of the US financial system.

Until now the United States has shied away from taking the same tough stance against North Korea, but the Trump administration has signaled it is not willing to accept Pyongyang's continued provocations.

In 2016, North Korea had exports worth around $3 billion, a vital source of revenue for the regime, according to the East-West Center.

Kim Jong-un's regime is trying to marry ballistic and nuclear technology to create a missile capable of delivering a nuke to the continental United States, and may be just months away from succeeding.

North Korea conducted its sixth and largest nuclear test on 3 September and has launched numerous missiles this year, including two intercontinental ballistic missiles and two other rockets that flew over Japan.

Last Tuesday, Mr Trump threatened to "totally destroy North Korea" if the United States is forced to defend itself or its allies against Pyongyang.

The announcement came as other major players on the world stage announced similar measures to press North Korea.

In Brussels, diplomatic sources told AFP that the European Union had agreed to a new package of measures, including a ban on investments in North Korea and on European Union exports of oil.

Mr Trump claimed that China's central bank has ordered its banks to curb trade with North Korea.

The Chinese move, which Mr Trump described as "very bold" and "unexpected," was not immediately confirmed by Beijing but if true could cut a vital source of foreign currency for the regime.

In Brussels, diplomatic sources told AFP that the European Union had agreed to a new package of measures, including a ban on investments in North Korea and on European Union exports of oil.

Mr Trump claimed that China's central bank has ordered its banks to curb trade with North Korea.

The Chinese move, which Mr Trump described as "very bold" and "unexpected," was not immediately confirmed by Beijing but if true could cut a vital source of foreign currency for the regime.