North Korea can indeed reach Washington with its latest ballistic missile, but it still needs to develop critical technology to deliver a nuclear warhead, senior South Korean officials have said.

Also, officials in president Moon Jae-in’s office said they have not discussed any military options with Washington against North Korea, including a naval blockade.

After a 75-day pause, North Korea test-fired a Hwasong-15 intercontinental ballistic missile (ICBM) on Wednesday, which flew 13,000 km, and Pyongyang proclaimed it was capable of putting the whole of the US mainland within its range. North Korean leader Kim Jong-un hailed the launch as a breakthrough, and declared his country had “completed the great historic cause of creating a state nuclear force”.

Jubilant from the success of the launch, North Korea released photographs and video footage of the missile, which analysts have been poring over for clues as to its effectiveness.

North Korea, which staged its sixth and largest nuclear bomb test in September, says it needs nuclear weapons to fend off the threat of a US invasion.

There has been debate in South Korea about whether the latest test means the North has crossed a “red line”. After it tested two ICBMs in July, Mr Moon said Pyongyang would cross a red line by creating a nuclear-tipped ICBM, and this could risk tougher moves from the US including military action.

“The government does not think that North Korea’s latest test demonstrated full capability for an ICBM, including re-entry technology and a precision guidance system. Seoul does not view the North as crossing the red line,” defence ministry spokesperson Yoo-jin Lee told a news briefing.

‘Calculative’ and ‘clever’

The Hwasong-15 is two metres longer than its predecessor, the Hwasong-14, and analysts were still examining the second-stage engine, he said.

South Korean defence minister Song Young-moo expected North Korea to pause its missile testing after the successful launch.

“Kim Jong-un is acting in a very calculative, clever manner,” Mr Song was quoted by the Yonhap news agency as saying.

“Kim changed the launch time, direction and distance in order to display he has this great power. He will probably make a great announcement in his new year’s address that the North has completed its weapons programme,” he said.

Part of this is down to seasonal factors. North Korea generally tests fewer weapons in the fourth quarter because the temperature drops significantly, putting pressure on fuel supplies, and also troops are required to help with harvests.

Analysts believe the launch shows that North Korea was only two or three tests away from being combat-ready.

Mr Moon and US president Donald Trump have held two telephone conversations in two days to discuss ways to rein in North Korea’s evolving missile technology.

Mr Trump is calling for stronger sanctions but some key players, including China and Russia, oppose beefing up sanctions. The US leader has said that China’s diplomatic efforts have been a failure, including despatching an envoy to Pyongyang. China has resisted US efforts for it to cut off North Korea’s oil supply.

Russia has weighed in with criticism of Mr Trump, accusing him of goading the North with his constant insults – he has called him a “sick puppy” and “Little Rocket Man”.

“One gets the impression that everything has been done on purpose to make Kim Jong-un snap and carry out further inadvisable actions,” foreign minister Sergei Lavrov said during a visit to Belarus. – (Additional reporting: agencies)