A Russian military plane made a series of flights between North Korea and the Russian Far East over the weekend, including a rare trip to a city where Kim Jong Un previously toured a fighter jet factory, in what experts described as a sign of ongoing sensitive consultations.

The Ilyushin Il-62M jet (RA-86559) operated by Russia’s Air Force first flew to Pyongyang from Vladivostok on Friday, spending about an hour at Sunan International Airport before departing at 12:37 p.m. KST, according to flight-tracking data from Flightradar24.