Over the weekend, North Korea claimed to have developed a new hydrogen bomb that it could fire as far as the United States.
South Korea's military said it believed the North's claim, and had detected seismic activity from the blast.
Last week, the Hermit Kingdom also launched a missile that passed over Japan and warned of more to come.
If its claims are true, the development would make North Korea far more dangerous to the global community than it has ever been before.
While Pyongyang's various provocations have prompted condemnation from almost the entire world, the most powerful nations involved seem unable to agree on what to do about them.
Scroll down to see what the key players in the North Korean issue have said.
The United States: More sanctions, more military action
Donald Trump's administration has repeatedly called for further sanctions and military action against the Pyongyang.
Following North Korea's claims of a sixth nuclear test, US Ambassador to the United Nations Nikki Haley told the Security Council that the country was "begging for war." The US is also preparing a draft UN resolution that would cut off all oil and fuel imports into North Korea, the New York Times reported.
Haley also hinted at military action: "Our country's patience is not unlimited. We will defend our allies and our territory."
Trump has made bolder threats. On Sunday, he tweeted that the US was "considering, in addition to other options," to stop trading with all countries with ties to North Korea. The US already announced sanctions against 16 Russian and Chinese companies and individuals, citing their ties with the North Korean regime, last month.
When asked whether he would attack North Korea, the US president also said: "We'll see."
In early August, the UN Security Council agreed to impose US-drafted sanctions on North Korea that would cut the country's export revenue by a third. Pyongyang called the decision a "heinous US plot to isolate and stifle" North Korea and threatened to exact "thousands-fold" revenge.
The United Kingdom: More sanctions, China should exert pressure
Britain's line on North Korea echoes that of the US.
Following Sunday's military test, UK Foreign Secretary Boris Johnson said, as cited by the Telegraph: "All options are on the table, but we really don't see any easy military solution.
"The distance between North Korea and Seoul is very, very small, and they [North Korea] could basically vaporise large parts of the South Korean population even with conventional weapons."
Johnson added that the idea of imposing harsher sanctions "still holds potential" and called on China to pressure the North Korean regime.
Prime Minister Theresa May also said last week that "China should be using its leverage with North Korea." She did not respond when asked whether the UK would commit troops to deter North Korea.
A House of Commons Library paper published last week noted that British troops could be deployed to help the US attack North Korea, even though it doesn't have to under NATO obligations.
South Korea: More sanctions, more talks
In light of Sunday's nuclear test, South Korea — which stands to lose the most in a North Korean war — has appeared to want more sanctions on Pyongyang.
The country also fired missiles into the sea to simulate an attack on the North on Monday, the Associated Press reported. But unlike the US, its president Moon Jae In has ruled out all-out war with the North.
"We can never tolerate another catastrophic war on this land,” his office said on Sunday evening, as cited by the New York Times. "We will not give up our goal of working together with allies to seek a peaceful denuclearization of the Korean Peninsula."
In a phone call that same day, Moon and Japanese Prime Minister Shinzo Abe affirmed their "understanding there must be the most powerful sanctions and pressure applied on North Korea" via the UN, a South Korean presidential spokesman told reporters.
The two leaders agreed that harsher sanctions would persuade North Korea to negotiate with the international community, the spokesman added.
In a separate phone call with Russian President Vladimir Putin on Monday, Moon also said the UN should "seriously consider to fundamentally block North Korea’s foreign currency sources by cutting off crude oil supplies and banning its overseas labour,"according to Bloomberg.
See the rest of the story at Business Insider