North Korea has launched what is thought to be its largest intercontinental ballistic missile to date, according to military officials in Japan and South Korea, in what would be the regime’s most serious provocation for years.

South Korea’s joint chiefs of staff said it had detected the launch of an “unidentified projectile” from North Korea on Thursday afternoon. South Korea said the launch was assumed to be a long-range missile, possibly an ICBM fired on a lofted trajectory, the Yonhap news agency reported.

If that is confirmed, it would be the first full-capability launch of the regime’s largest missiles since 2017, and a sign that it has made significant progress in developing weapons capable of delivering nuclear warheads anywhere in the US.

Japan’s prime minister, Fumio Kishida, described the launch as “reckless”, while the state minister of defence, Makoto Oniki, said the missile was possibly a new type of ICBM.

Oniki said the missile had flown for about an hour before landing inside Japan’s exclusive economic zone [EEZ] about 90 miles west of the Oshima peninsula on Hokkaido, Japan’s northernmost main island, at 3.35pm local time. There were no reports of damage to aircraft or vessels in the area.

“At a time when the world is dealing with Russia’s invasion of Ukraine, North Korea is pressing ahead with launches that unilaterally aggravate provocations against the international community, which is absolutely unforgivable,” Oniki said.