The British Government has refused to rule out joining its US ally in using military force against North Korea after Donald Trump threatened to totally destroy the rogue state if attacked.
He sparked gasps of shock among members as he called dictator Kim Jong-un a rocket man on a suicide mission for himself and his regime.
Downing Street has since confirmed it would consider joining Mr Trump in military action against North Korea.
In a statement, a spokeswoman said no-one wants to see military action but it would be wrong to rule anything out.
Mr Trump has been criticised in some quarters for his inflammatory rhetoric as North Korea has escalated its nuclear and missile tests in recent weeks, but he told the UN: Rocket man is on a suicide mission for himself and his regime.
Speaking about the US, he added: If it is forced to defend itself or its allies, we will have no choice but to totally destroy North Korea.
The US President also urged UN member states to work together to isolate the Kim government until it ceases its “hostile” behaviour in the form of several recent missile launches that have sparked global outrage.
In the lengthy maiden speech to UN delegates, Mr Trump also attacked Iran and Venezuela while criticising the UN itself for allowing countries with human rights violations to sit on the international body’s human rights panel.
Following Mr Trump’s address, a Number 10 spokeswoman said: “We are clear that North Korea’s actions are provocative and destabilising and our focus is on increasing the pressure on them to change course.
As President Trump said, the international community must continue to work together to confront rogue regimes and that is exactly what the Prime Minister will be doing in discussions with world leaders in New York this week.
No-one wants to see military action, but as we progress with efforts to secure a peaceful diplomatic resolution it would be wrong to rule anything out.
The speech came after North Korea threatened to speed up its nuclear programme if the UN continued to impose sanctions on the rogue state.
In a strongly worded statement released on Monday, Pyongyang described a new set of UN sanctions as the most vicious, unethical and inhumane act of hostility.
Foreign Secretary Boris Johnson urged Chinese foreign minister Wang Yi to keep up the pressure on North Korea after the pair met at the UN in New York.
Mr Johnson also met Japanese foreign minister Taro Kono and reiterated the UK’s solidarity with Japan over the threat it faces from Mr Kim’s regime.
Speaking after the meetings, the Foreign Secretary said: “China has a vital role to play and unique economic influence over North Korea. It controls more than 90% of North Korea’s external trade, including its oil supplies, making them perfectly placed to put the kind of pressure on Kim Jong Un that will make him take notice.
As the Prime Minister said during her recent visit to Japan, the UK stands shoulder to shoulder with them in the face of North Korean aggression.
Last week the harshest UN sanctions placed on any nation in the 21st century were imposed on North Korea. They must now be enforced.