North Korea is seeking a peace treaty with the US, China and South Korea to formally end the Korean War and will not stop its nuclear tests until it gets one, a person who relayed that message from North Korea to China told Reuters.

North Korea announced last Wednesday it had carried out its fourth nuclear test since 2006, drawing threats of more sanctions, although US and weapons experts doubted Pyongyang’s claim that the device was a hydrogen bomb.

The test has again raised questions among world powers about what can be done to stop the North’s nuclear weapons program.

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The source, who has contacts in the North Korean capital of Pyongyang and provided exclusive details about the preparations for the first nuclear test in 2006, said the tests would go on until the North’s demand for a treaty was met.

North Korea and the US have been bitter rivals in recent years. Photo: AAP

“North Korea will do it to the end until China and the United States want to sign a peace treaty,” said the source, who declined to be identified.

The 1950–53 Korean War ended in an armistice, not a peace treaty, signed by the US, representing UN forces, the North Korean military and the Chinese army.

Now, North Korea wants those three sides and South Korea to sign a treaty.

“This explosion is mainly for the United States to see. The main objective is to persuade the United States to enter into four-country negotiations to end the war so that there can be everlasting peace on the Korean peninsula,” the source said.

North Korea has repeatedly said it wants a peace treaty to formally end the war, which it says will give it the security it needs, given what it sees as a hostile US intent on “regime change” in Pyongyang.

The US and China have dangled the prospect of better ties, including the lifting of sanctions and eventually a likely peace treaty, if North Korea gives up its nuclear weapons.

But North Korea believes the US will only negotiate if Pyongyang can demonstrate its strength through its weapons.

With its demand for a treaty ignored, North Korea has continued to develop its nuclear weapons and a stalemate has ensued.

The source said he had relayed the message from North Korea to China’s top leadership immediately after its latest test, urging China to support a push for a treaty.

“China should not follow the United States,” the source said, referring to the US demand that North Korea give up its nuclear program before any negotiations.

“Not mentioning a peace treaty is a strategic mistake.”