The tense stand-off between the US and North Korea over the rogue state's nuclear weapons programme continued as Washington warned the crisis was coming to a head.
US national security adviser HR McMaster insisted Pyongyang would not be allowed to threaten its neighbours and America with a nuclear arsenal.
“This problem is coming to a head. And, so, it's time for us to undertake all actions we can short of a military option to try to resolve this peacefully."
Mr McMaster gave the blunt assessment that Pyongyang's stance "just can't continue" after its failed missile launch on Sunday.
The as-yet unidentified missile exploded on launch from a base in Sinpo, a city on the country's east coast, said the US.
Mr McMaster indicated that Washington was working with China to try and find a way out of the crisis.
"The president has made clear that he will not accept the United States and its allies and partners in the region being under threat from this hostile regime with nuclear weapons.
"And so we are working together with our allies and partners, and with the Chinese leadership, to develop a range of options."
President Donald Trump talked tough on the country's resolve, tweeting: "Our military is building and is rapidly becoming stronger than ever before. Frankly, we have no choice!"
Amid speculation that Pyongyang may attempt another nuclear test in the coming days, Mr Trump also signalled that China could receive a better trade situation with the US if it was constructive in dealing with the North Korean regime.
Downing Street would not be drawn on reports that Prime Minister Theresa May had privately urged Mr Trump not to launch air strikes on North Korea.
Labour MP Barry Gardiner told the BBC: "Why privately? You don't urge this privately as Prime Minister of this country, you come out and you say that we should be working multilaterally through the United Nations, not going behind closed doors in a private telephone conversation.
"You come out and you say it publicly."
Number 10 pointed to a tweet by Foreign Secretary Boris Johnson as representing the Government position in which he stated: "I strongly condemn the latest North Korean missile launch. They must stop these belligerent acts and comply with UN resolutions."
Mr Trump ordered aircraft carrier USS Carl Vinson and several warships to the area to highlight American concern at the situation, as China expressed fears war could erupt "at any moment", while Pyongyang warned it could launch a nuclear strike if it feels threatened.
Former Conservative foreign secretary Sir Malcom Rifkind said it was possible that the missile either malfunctioned or was sabotaged by a US cyber attack.
Meanwhile, Russian ambassador to the UK Alexander Yakovenko accused Britain of "raising tensions in Europe" by deploying 800 troops to Nato's eastern border, the Daily Mail reported.