North Korea might launch an intercontinental ballistic missile (ICBM) on Saturday, as the country marks the anniversary of its founding, South Korean Prime Minister Lee Nak-yon on Thursday.

“The situation is very grave. It doesn’t seem much time is left before North Korea achieves its complete nuclear armament,” CNN quoted the Prime Minister as saying at a meeting of defence officials here.

“A special measure is urgently needed to stop their recklessness.”

Earlier on Thursday, the final parts of the American Terminal High Altitude Area Defence (THAAD) missile system arrived at a base in South Korea as hundreds of protesters thronged the area amid a huge police presence.

Protesters scuffled with armoured riot police as they attempted to block the road where US Forces Korea were transporting four additional THAAD missile interceptor launchers to a base in Seongju, around 300 km south of Seoul.

Two launchers have been operational at the site since May, CNN reported.

The rollout was “temporarily” completed Thursday, a spokesman for South Korea’s Defence Ministry said, adding it was necessary to counter increased threats from North Korea.

On Thursday morning, South Korean President Moon Jae-in met with Japanese Prime Minister Shinzo in Vladivostok where they are attending the Eastern Economic Forum, hosted by Russian President Vladimir Putin.

After the meeting, Abe and Moon issued a statement saying “now is the time to further increase sanctions and pressures against the North as much as possible rather than seeking dialogue”n.

The two leaders felt Russian and Chinese involvement was paramount and agreed to work towards that goal. Abe is due to meet Putin separately later in the day.