North Korean leader Kim Jong-un on Wednesday boasted of a surge of internal strength in the new year because of the elimination of ``factionalist filth'' _ a reference to his once powerful uncle and mentor, whose purge and execution last month have raised questions about the country's stability.

Kim's comments in an annual New Year's message, including those focusing on one of the biggest political developments in Pyongyang in years, and certainly since the young leader took power two years ago after the death of his father, Kim Jong Il, will be closely scrutinized by outside analysts and governments for clues about the opaque country's intentions and policy goals.

North Korea's ``resolute'' action to ``eliminate factionalist filth'' within the ruling Workers' Party has bolstered the country's unity ``by 100 times,'' Kim said in a speech broadcast by state TV.

Analysts are divided about what Jang Song-thaek's execution on treason charges means, but many believe it shows Kim Jong Un has yet to establish the same absolute power that his father and grandfather enjoyed. Jang was widely considered the country's No.2 power.

Officials in Seoul say potential instability in the North could lead to the country launching provocations against South Korea to help consolidate internal unity. Attacks blamed on North Korea killed 50 South Koreans in 2010, and tension on the Korean Peninsula still lingers, although Pyongyang has backed away from war rhetoric from early last year that included threats of nuclear attacks against Washington and Seoul.

North Korea has also vowed to restart nuclear bomb fuel production. The country conducted its third nuclear test in February and is estimated to have a handful of crude nuclear devices and to be working toward building a warhead small enough to mount on a long-range missile. Most experts say that goal may take years to achieve.

The rival Koreas share one of the world's most heavily armed borders, with hundreds of thousands of combat-ready troops facing each other along the mine-strewn Demilitarized Zone. The 1950-53 Korean War ended with an armistice, not a peace treaty, leaving the peninsula technically in a state of war. About 28,500 American troops are deployed in South Korea to help deter North Korean aggression.

During his two years in power, Kim Jong-un has overseen nuclear and missile tests, other high-profile purges and a barrage of threats. His father took a much more low-profile approach when he took over after Kim Il -sung's 1994 death. 

Kim Jong-un, who also spoke publicly last New Year's Day, appears to be following in his grandfather's steps, the country's founder Kim Il-sung, who gave public New Year's readings on state television and radio until his 1994 death. Under the more private Kim Jong-il, the North's leading newspapers released the annual statement in a joint editorial. (AP)