North Korea has called back its top diplomats to China and the United Nations. 

According to sources in Beijing on Tuesday, an Air Koryo flight carrying North Korean ambassador to China Ji Jae-ryong and North Korean Ambassador to the UN Kim Song departed for Pyongyang from Beijing on Tuesday afternoon. 

Both diplomats are believed to have played a significant role in negotiations with Washington on denuclearization and the peace process on the Korean Peninsula. 

There is speculation that Pyongyang summoned the two back to discuss Washington’s apparent considerations to strengthen sanctions on the regime as well as how North Korea should respond following the collapse of the second North Korea-U.S. summit last month.