Signs of the resumption of activity at some military test sites in North Korea have been observed, less than two weeks before the year-end deadline the regime set for denuclearization negotiations with the United States.

Amid speculation that the North may carry out a military provocation, experts say its actions may involve tests for the development of submarine-launched ballistic missiles and intercontinental ballistic missiles capable of carrying multiple warheads.

According to a report released Monday by the Korea Institute for Defense Analyses, Pyongyang may launch something more provocative than short-range ballistic missiles and multiple rocket launchers it has previously fired, and pressure Washington for concessions, if the two sides fail to make progress in their stalled negotiations by early 2020.

As the North has said it will give a “Christmas gift” to the US depending on the progress made in denuclearization negotiations, the regime may review the option to launch a satellite into orbit, KIDA said in the report “2020 Defense Environment Prospects and Tasks.”

Firing weapons that threaten the US may be too risky for Pyongyang. Therefore, a satellite launch -- a nonmilitary action -- could be an option that would demonstrate its ability to fly a rocket that could reach US territories.

If negotiations with Washington break down, Pyongyang may work to develop submarine-launched ballistic missiles and a multiple reentry vehicle.

“If the denuclearization negotiations with the US breaks down, Pyongyang would make efforts to manifest its retaliatory power against Washington, to keep the military pressure from the US in check,” the report said.

South Korea’s military confirmed that the latest tests conducted by the North at the Sohae Satellite Launching Ground, revealed Dec. 8 and 14, involved a new engine for a long-range missile.

While opinions vary, some experts believe that the regime tested solid-fuel engines, which are more efficient and powerful -- suitable for a multiple reentry vehicle.

Jeffrey Lewis of the Middlebury Institute of International Studies in the US assessed that Pyongyang has the major technologies to launch ICBMs and may even be able to build a reentry vehicle.

“That’s a goofy thing people keep talking about. There’s never been a country that has been able to build an ICBM that hasn’t been able to build a reentry vehicle,” Lewis told Voice of America, a US-based news outlet.

Regarding the latest test that Pyongyang is believed to have conducted from 10:41 p.m. to 10:48 p.m. on Dec. 13, Lewis said the test time could be associated with advanced weapons concepts.

“Seven minutes is a really a long burn time, so that raises all the things that are associated to relatively advanced concepts like orbital bombardment or multiple warheads,” Lewis said.

By Jo He-rim (herim@heraldcorp.com)