North Korean President Kim Jong Un told a ruling party congress that his country would not use nuclear weapons unless its sovereignty was threatened by other nuclear powers, North Korea’s state news agency said Sunday.

Kim also said he was willing to normalise relations with states that have been hostile toward the Pyongyang government, and he called for more talks with South Korea to reduce distrust and the potential for further misunderstandings, the Korean Central News Agency report said.

“As a responsible nuclear weapons state, our republic will not use a nuclear weapon unless its sovereignty is encroached upon by any aggressive hostile forces with nukes,” the report quoted Kim as saying.

It was unclear whether Kim’s pledge indicated any change in North Korea’s often belligerent attitude toward its neighbors and the United States. In March, North Korea threatened a “preemptive” and “indiscriminate” nuclear strike on the U.S. and South Korea in response to the two nations’ joint military drills.

Kim’s comments to a reported 3,400 delegates came as South Korean monitors remained on high alert over the threat of further nuclear-related testing by the North in the near future.

The United Nations toughened sanctions against Pyongyang in March, after the communist state’s fourth nuclear test and the launch of a long-range rocket that was widely seen as a disguised ballistic missile test.

The website 38 North, which focuses on North Korean issues, said Friday that commercial satellite images taken the day before over Pyongyang’s nuclear test site showed vehicle movement at a command center, where there is often no activity “except during preparations for a test.”

Kim opened the seventh Workers’ Party Congress on Friday by hailing the country’s January nuclear test and February launch of a satellite into space, calling them demonstrations of “dignity and power at the highest level.”

“In this year of the seventh party congress, our military and people accomplished the great success in the first hydrogen bomb test and the launch of an earth observation satellite,” Kim said.

In response, Washington called on Pyongyang to “refrain from actions and rhetoric that further destabilise the region.”

•Excerpted from a VOA report. Photo shows North Korean President Kim Jong Un.

Update news