Washington – Recent satellite photos suggest North Korea could be preparing for fresh submarine-based ballistic missile tests, an expert on its military said Friday.

Joseph Bermudez, a specialist in North Korean defense and intelligence affairs, posted photographs on the authoritative 38 North blog of the US-Korea Institute at Johns Hopkins University which he said could show preparations for a test of a submarine-launched ballistic missile (SLBM).

“Recent commercial satellite imagery reveals several developments suggesting that North Korea may be accelerating the development of the sea-based leg of its nuclear forces,” he said.

Activity on a SINPO-class experimental ballistic missile submarine at the Mayang-do navy shipyard and submarine base, he said, suggests “that the North may be preparing for a new series of ‘at sea’ test launches, has undertaken modifications or upgrades to the submarine’s launch systems, or is developing a more advanced version of the Pukguksong-1.”

The Pukguksong-1 is an SLBM that was first successfully test-launched on August 24, 2016.

© AFP JUNG YEON-JE This file photo from August 25, 2016 shows people walking past a television screen at a railway station in Seoul reporting news of a North Korean submarine-launched ballistic missile test

© AFP JUNG YEON-JE – This file photo from August 25, 2016 shows people walking past a television screen at a railway station in Seoul reporting news of a North Korean submarine-launched ballistic missile test