Kim boasted on Wednesday that his regime had been bolstered by the elimination of a divisive element, after the purge that saw his once-powerful uncle executed.
In his first words of personal public criticism for Jang Song Thaek, Kim said the move had strengthened the ruling Worker's Party "by 100 times."
"Our party took resolute action to remove... scum elements within the party last year," Kim said. The young leader accused Jang - who was widely held to be the country's second most powerful individual - of trying to build his own powerbase within the ruling party.
"Our party's timely, accurate decision to purge the anti-party, anti-revolutionary elements helped greatly cement solidarity within our party," he said.
Jang, who had served as Kim's political mentor, was put to death - reportedly by machine gun fire - on December 12 after a speedy corruption and treason trial. The purge was the biggest political upheaval since Kim took power after the death of his father Kim Jong-Il, in December 2011.
'Worse than a dog'
The execution prompted speculation that Jang - who the North's official news service described at the time as "worse than a dog" - had lost out in a power struggle with hardline generals. Kim, aged around 30, has removed most of Pyongyang's old guard in a little over two years in charge, replacing aging generals and officials with individuals nearer his own age.
In his message, Kim also called for an improvement in relations with South Korea, calling for Seoul to strive towards reunification. He also warned of a "massive nuclear disaster" should war break out on the peninsula, adding that the US would "never be safe" in the event.
rc/av (AFP, AP)