Destroying the roads would be in line with Kim Jong Un's push to cut off ties with South Korea and abandon the decades-long objective to seek a peaceful unification.
Vladimir Putin and Kim Jong Un signed a treaty upgrading their relationship and pledging military assistance if either one is attacked, drawing criticism from NATO, South Korea and other countries.
In a summit in Russia, President Vladimir Putin and North Korean leader Kim Jong Un showed how geopolitical tensions have brought the two neighbors isolated by the West into closer alignment.
On Monday, a dark green train with yellow trim was spotted at the border where Russia, China and North Korea meet. It runs with one passenger in mind: the leader of North Korea, Kim Jong Un.
Questions about the dynastic ruler's children and possible succession scenario arose with the apparent second child's repeated appearances in public in public in recent months.
His young daughter Kim Ju Ae also attended. Some observers interpret this as Kim's message that nuclear weapons will protect future generations of North Koreans.
North Korea is marking a key state anniversary Friday with calls for stronger loyalty to Kim Jong Un, but there was no word on an expected military parade amid heightened international tension.