Washington: US President Donald Trump on Sunday said the latest nuclear test by North Korea posed a danger to the US and raised questions about South Korea's ability to control Pyongyang.
"North Korea has conducted a major nuclear test," Trump said in a series of Twitter posts. "Their words and actions continue to be very hostile and dangerous to the US."
The US President tweeted that North Korean leader Kim Jong-un's regime had again violated international law with the test of a hydrogen bomb at the Punggye-ri site, Efe news reported.
The explosion caused a 6.3-magnitude earthquake and North Korean state media confirmed that a bomb with "unprecedented power" had been successfully tested on the orders of leader Kim Jong-un.
"North Korea is a rogue nation which has become a great threat and embarrassment to China, which is trying to help but with little success," Trump tweeted.
He also warned South Korea that its strategy for dealing with Pyongyang had been a failure.
"South Korea is finding, as I have told them, that their talk of appeasement with North Korea will not work, they only understand one thing!" Trump said.
The hydrogen bomb test follows North Korea's August 29 launch of a ballistic missile that landed in the Pacific off northern Japan.
North Korea said the miniaturised hydrogen bomb can be mounted on an intercontinental ballistic missile (ICBM).