North Korea is ready to launch a nuclear test at its Punggye-ri Nuclear Test Site, the 38 North monitoring group reported.

The 38 North analysis group described the test site as 'primed and ready'.

'Commercial satellite imagery of North Korea's Punggye-ri Nuclear Test Site from April 12 shows continued activity around the North Portal, new activity in the Main Administrative Area, and a few personnel around the site's Command Centre,' the North Korea-related analysis website said.

The Voice of America said last night, quoting US government and other sources, that North Korea 'has apparently placed a nuclear device in a tunnel and it could be detonated Saturday AM Korea time'.

On Sunday, the US had sent an aircraft carrier-led strike group toward the Western Pacific Ocean near the Korean Peninsula 'in response to recent North Korean provocations'.

Last week, North Korea launched a Scud extended-range missile, which US officials said exploded in flight.

US intelligence officials say Pyongyang could be less than two years away from developing a nuclear warhead that could reach the continental United States. -- Agencies