A U.S. Web site monitoring North Korea has claimed that the North's Punggye-ri nuclear test site is "fully operational" contrary to speculations that it is already unusable. 

38 North said on Monday that as far as it can tell, the test site, where North Korea has conducted six acknowledged underground detonations, is still fully operational. 

It said that the site could be reactivated when necessary, noting that North Korea appeared to have abandoned the North Portal after its sixth nuclear test in September, but "significant new tunneling" was spotted at the West Portal through early March. 

38 North said that renewed tunneling was curtailed by mid-March, but not entirely stopped through early April, suggesting that either the tunnel was complete and ready for future renewed testing or that the slowdown simply mirrored the ongoing political changes under way.

It added that there is no basis to conclude that the test site is no longer viable for future nuclear testing and there remain two portal areas that can be used for future tests if Pyongyang were to give the order.

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