North Korea appears to be on an “aggressive schedule” to build and deploy its first operational ballistic missile submarine, according to an analysis posted on Thursday by 38 North. Such a missile sub would be capable of hurling a nuclear payload at a US target.

Analyst Joseph S. Bermudez Jr. says in an article posted on the specialist website on North Korea that commercial satellite imagery of the Sinpo South Shipyard from November 5 suggests the construction of a new submarine. He says the vessel could be a SINPO-C ballistic missile submarine — the follow-on to the current SINPO-class experimental ballistic missile submarine.

Bermudez noted the photos show continued movement of parts and components into and out of the parts yards adjacent to the facility’s construction halls, indicating an ongoing shipbuilding program.

“A probable launch canister support, or launch canister, appears to be present within the service tower at the missile test stand suggesting the ongoing ejection testing of submarine launch ballistic missiles,” Bermudez wrote. “Such testing could support the continued development of (submarine-launched ballistic missiles), a new ballistic missile submarine or a combination of both.”

US officials disclosed to US news network CNN on July 31 that they had detected “highly unusual and unprecedented levels” of activity at the Sinpo shipyard, amid reports of successful “ejection tests” of sub-based missiles at the facility.

Three ejection tests were carried out on land at Sinpo Naval Shipyard in July alone, US officials told CNN. Another test was conducted at the facility, which is the headquarters of the Maritime Research Institute of North Korea’s Academy of National Defense Science, earlier in the year.