The North is banned under U.N. sanctions from developing missile or nuclear technology after its 2006 and 2009 nuclear tests.

North Korea worked to ready its nuclear test site, about 100 km (60 miles) from its border with China, throughout last year, according to commercially available satellite imagery. The images show that it may have already prepared for at least one more test, beyond Tuesday’s subterranean explosion.

“Based on satellite imagery that showed there were the same activities in two tunnels, they have one tunnel left after the latest test,” said Kune Y. Suh, a nuclear engineering professor at Seoul National University in South Korea.

Analysis of satellite imagery released on Friday by specialist North Korea website 38North showed activity at a rocket site that appeared to indicate it was being prepared for an upcoming launch (here).

NORTH ‘NOT AFRAID’ OF SANCTIONS

President Barack Obama pledged after this week’s nuclear test “to lead the world in taking firm action in response to these threats” and diplomats at the U.N. Security Council have already started discussing potential new sanctions.

The North has said the test this week was a reaction to what it said was “U.S. hostility” following its December rocket launch. Critics say the rocket launch was aimed at developing technology for an intercontinental ballistic missile.

“(North) Korea is not afraid of (further) sanctions,” the source said. “It is confident agricultural and economic reforms will boost grain harvests this year, reducing its food reliance on China.”