Kim Jong Un rules North Korea with an iron fist. Title change will mean little to the way he wields power

North Korea's parliament has approved changes to the country's constitution to solidify leader Kim Jong Un's role as head of state, state media said on Thursday.

The move comes after Kim was formally named head of state and commander-in-chief of the military in a new constitution in July that analysts said was possibly aimed at preparing for a peace treaty with the United States.

North Korea has long called for a peace deal with the United States to normalize relations and end the technical state of war that has existed since the 1950-1953 Korean War, concluded with an armistice, rather than a peace treaty.

Kim's legal status as "representing our state has been further consolidated to firmly ensure the monolithic guidance of the Supreme Leader over all state affairs," state news agency KCNA quoted Choe Ryong Hae, president of the presidium of the supreme people's assembly, or titular parliament, as saying.

The presidium president had historically been the nominal head of state.

But the new constitution said Kim, as chairman of the State Affairs Commission (SAC), a top governing body created in 2016, was the supreme representative of all the Korean people, which means head of state, as well as "commander-in-chief".

A previous constitution simply called Kim "supreme leader" who commanded the country's "overall military force".

Thursday's constitutional amendments appear to confirm that North Korea's legal system will now recognise Kim as head of state.

The new constitution authorises Kim to promulgate legislative ordinances and major decrees and decisions and appoint or recall diplomatic envoys to foreign countries, KCNA said.

"With the amendment, Kim Jong Un is reviving his grandfather's head of state system," said Cheong Seong-chang, a senior fellow at the Sejong Institute. "He has become a de facto head of state."

In reality Kim, a third-generation hereditary leader, rules North Korea with an iron fist and the title change will mean little to the way he wields power.

The back-to-back constitutional revision is unprecedented, said Rachel Minyoung Lee, an analyst with NK News, a website that tracks North Korea.

"By further bolstering the SAC chairman's authority, Kim Jong Un has emerged as the most powerful leader in North Korean history," she said.

There has been scant progress in the U.S. aim of getting North Korea to give up its nuclear weapons programme despite three meetings between President Donald Trump and Kim.

Trump has said he and Kim agreed at their last meeting to resume working-level talks, but these have yet to happen and North Korea has conducted multiple missile tests since, while accusing Washington of breaking a pledge to stop joint military exercises with South Korea.