North Korean supreme leader Kim Jong Un said Wednesday that national unity had strengthened “by 100 times” following the purge of “counterrevolutionary factionalists” — an apparent reference to his uncle, Jang Song Thaek, who was executed last month for treason.

Kim’s comments, delivered in a lengthy New Year’s Day address, were his first since Jang was accused of plotting a coup and stripped of all his posts. Although Kim did not mention Jang by name, he described the purge as the “correct decision.”

Kim also said the North must be more vigilant in stamping out dissent and called for intensified ideological education for Workers’ Party members and citizens to “ensure that they think and act at all times and in all places in line with the Party’s ideas and intentions.”

North Koreans “should wage a vigorous struggle to stamp out any sort of alien ideology and decadent lifestyle that may undermine our system,” Kim said.

The acknowledgment of potential dissent is noteworthy because the Pyongyang government has for decades used its propaganda to project a sense of unquestioned loyalty to the Kim family. Some analysts say that under Kim, the North has abruptly abandoned that kind of mythmaking and is instead highlighting the punishment that disloyalty will bring.

Kim, who will turn 31 next week, assumed power in the North after the death of his father, Kim Jong Il, in December 2011. Jang’s removal represents the highest-level shake-up during his tenure, and experts are uncertain whether the move will help Kim consolidate power or bring further chaos.

Analysts who study the authoritarian nation say its leader’s annual New Year’s address provides some hints about its policy goals — as well as plenty of by-the-numbers propaganda. Much of Kim’s address Wednesday focused on modest steps for improving agriculture and the economy. Kim also said a “favorable climate” should be established to improve relations with South Korea — although he laid out a similar vision a year ago, only to threaten Seoul with a military attack in March and April.

This was at least the third time that Kim has delivered a speech to mark a major holiday. The approach contrasts with that of his father, who ruled for 17 years and addressed North Korean citizens only once. During Kim Jong Il’s tenure, the annual address took the form of an editorial published by the main state-run newspapers.

For all of the younger Kim’s talk about bolstering the economy, he made no mention Wednesday of international trade or foreign investment — areas in which Jang had been heavily involved.

“It implies that North Korea is going to focus more on domestic matters,” said Park Hyeong-jung, a North Korea researcher at Seoul’s Korea Institute for National Unification.

South Korea’s unification minister told lawmakers Monday that the North was continuing to purge officials who had been close to Jang. That group is seen as likely to include the North’s ambassador to Sweden, Pak Kwang Chol, who has been summoned back to Pyongyang, according to the South’s Yonhap news agency.

Last month, South Korean President Park Geun-hye warned that the North might attempt a military provocation, given the uncertainty of its “political situation.” Kim’s speech Wednesday was light on war rhetoric, but he did blast the United States and South Korea for staging military exercises, calling them a rehearsal for a nuclear war against the North.

“Should another war break out on this land,” Kim said, “it will result in a deadly nuclear catastrophe, and the United States will never be safe.”

Yoonjung Seo contributed to this report.