North Korean leader Kim Jong Un
North Korean leader Kim Jong UnReuters

North Korean dictator Kim Jong-Un told a rare ruling party congress on Saturday that North Korea would only use nuclear weapons if attacked by a nuclear power, adding he wanted improved relations with previously "hostile" nations.

Speaking to thousands of delegates gathered for the first Workers' Party congress in more than 35 years and quoted by AFP, Kim also promised that the North would pursue a policy of non-proliferation and push for global denuclearization.

Kim had opened the congress with a defiant defense of his country’s nuclear weapons program, praising the "magnificent... and thrilling" test of what Pyongyang claimed was a powerful hydrogen bomb on January 6.

North Korea last month held a successful submarine nuclear missile launch that is said to bring the United States within range. Despite the successful tests, however, the rogue state has also embarrassingly failed two missile tests in recent weeks.

Despite the tests, Kim’s report to the conclave on Saturday stressed that North Korea's status was that of a "responsible" nuclear weapons state, according to AFP.

"Our republic will not use a nuclear weapon unless its sovereignty is encroached upon by any aggressive hostile forces with nukes," he said.

The Korean-language version of his address made it clear that the scenario involved an actual nuclear attack on the North.

He also vowed that Pyongyang would "faithfully fulfil" its non-proliferation obligations and push for global denuclearization, the North's official KCNA news agency said.

North Korea withdrew from the global Non-proliferation Treaty (NPT) in 2003 -- the first signatory country to do so.

At the time of the first nuclear test in 2006, North Korea stated it would "never use nuclear weapons first", but has since made repeated threats of pre-emptive nuclear strikes against South Korea and the United States.

In his address, however, Kim also waved what might be taken as a potential olive branch, stating that North Korea would seek to improve and normalize relations with friendly countries, "(even) though they had been hostile in the past."

There has been speculation that, in the wake of the party congress, Pyongyang might renew its push for talks with Washington.

The United States and North Korea have held a number of informal discussions in neutral venues in recent years, but they are understood to have stalled over the basis for beginning any substantive dialogue.

In February, there were conflicting reports regarding a proposal for renewed United States-North Korea peace talks.

The State Department insisted that Washington rejected a North Korean proposal to discuss a peace treaty to formally end the Korean War because it did not address denuclearization on the peninsula.

But a report earlier in the Wall Street Journal suggested the opposite - that it was the United States that offered the peace treaty and that Pyongyang had been the one to reject it.