North Korean leader Kim Jong Un led events commemorating the second anniversary of his father's death, just days after the execution of the uncle who was thought to be his mentor and second in command.
Mr. Kim joined other top military and political leaders Tuesday at a somber memorial service at a Pyongyang auditorium where an image of his father, ex-North Korean leader Kim Jong Il was hanging on stage.
One of the speakers was Choe Ryong Hae, the director of the powerful Army General Political Department.
"As we recall the revolutionary life and indelible achievements of our Generalissimo Kim Jong Il, we are strengthening our will and belief to honor the Great General Kim Jong Un's ideas and military power by obeying his 'military-first' revolutionary policy."
Others also pledged unwavering loyalty to the Kim dynasty, promising to protect the country with their lives and saying the country has made progress since the younger Kim took over.
The elder Kim died unexpectedly in December 2011, leaving power to his young and inexperienced son, who has been replacing some of the country's top leaders in an effort to consolidate power.
Last week, Pyongyang announced the execution of Jang Song Thaek, a once-influential figure who had been viewed as a mentor to the younger Kim following his father's death.
Jang, who was married to Kim Jong Il's sister Kim Kyong Hui, was accused of trying to overthrow the state, along with a series of other abuses, such as corruption, womanizing and drug use.
Kim Kyong Hui, herself a powerful figure, did not appear on stage in videos of the ceremony that appeared on state media. There has been speculation about whether she survived the purge of Jang's associates, some of whom were also executed.
There is disagreement about what Jang's execution means for the notoriously secretive North Korean leadership. Most Korea watchers were surprised at Pyongyang's acknowledgement of dissension within its ranks.
North Korea's neighbors, meanwhile, are watching closely for possible military provocations from the nuclear-armed North.
South Korean defense ministry spokesman Kim Min-seok said Tuesday it is "highly likely" Pyongyang will carry out provocations between late January and early March.
"They may try to partially strengthen the sole leadership with the reign of terror, but anxiety of North Korean people and other power groups will grow. Making a military provocation is a conventional way to relieve the anxiety."
North Korea has already conducted three nuclear weapons tests in recent years, and held several long-range missile launches, both of which are banned by United Nations sanctions.