Singapore: North Korea has added a structure to a factory linked to the production of intercontinental ballistic missiles, NBC News reported, raising concerns the reclusive country will resume testing weapons that can reach the US.

The commercial satellite images from Planet Labs show a temporary structure added to the site that can accommodate the raising of a launcher arm for such long-range missiles. The news report cited an analysis by Jeffrey Lewis, director of the East Asia Nonproliferation Program at the Middlebury Institute of International Studies.

orth Korean leader Kim Jong Un speaks during a ruling party meeting on Sunday. Credit:KCNA/AP

The hermit state has engaged in a series of weapons tests as Kim approaches his self-imposed year-end deadline for US President Donald Trump to make a better offer in negotiations. The two sides have recently resumed threats and insults, with North Korea warning that it was preparing a choice of "Christmas" gifts for Trump, depending on his response.

North Korea last launched an intercontinental ballistic missile in November 2017, a breakthrough test that demonstrated Kim's ability to carry nuclear warheads to the entire US mainland. Kim subsequently declared his nuclear weapons program "complete" and opened talks with South Korea and later with Trump. But he talks have since collapsed.

Bloomberg