Early this year, North Korean leader Kim Jong-un ordered officials to invite any senior figures from abroad to the party anniversary, according to the source. But almost none have bitten, not even in nominally allied countries.
Contrary to their earlier promise, former Indonesian President Megawati Sukarnoputri and senior Vietnamese apparatchik Ngo Van Du have reportedly canceled their scheduled visit.
In Cuba, Leopoldo Cintra Frias, the armed forces minister, has not yet responded to the invitation.
Antonio Razzi, an Italian senator who has visited the North several times, has reportedly declined the invitation for fear that he would be taken advantage of by the regime's propaganda machine.
In Beijing, a diplomatic source said, "With only 10 days left before the anniversary, I haven't heard that China has received a formal invitation." It is unclear whether that is linked to China's firm opposition to another North Korean long-range missile test.
"During the UN General Assembly session, Chinese President Xi Jinping openly warned the North against any provocations," the source added. "China would lose face if the North did go ahead with a missile launch while a senior Chinese official is in the country."