North Korea is planning a new nuclear test in the area where it staged previous atomic blasts, according to a report from South Korean intelligence officials obtained by CNN.

The intelligence report has come to light as North Korea gets ready to carry out a controversial rocket launch this week, a move that would further strain ties between the reclusive, nuclear-armed state and other countries in the region. The planned rocket launch is scheduled to take place just months after the ascendancy of its new leader.

The South Korean intelligence report says it is highly probable that after the long-range rocket launch, North Korea will use the ensuing international condemnation as an excuse to go ahead with the nuclear test in Punggye-ri, the site in the country’s northeast where the other two tests were conducted in 2006 and 2009.

The report, which said such a test would be considered a grave provocation, includes satellite images that it claims were filmed recently and show the final stages of a tunnel being dug at the site.

The photos show an unusual pile of earth and sand near the opening of the tunnel, and the report says this pile has been slowly increasing since March.

North Korean state media have not made an announcement regarding plans for a new nuclear test. Two senior U.S. officials said the United States also had reason to believe that the North was planning such an action.

READ MORE: CNN