Major structures built to promote the personality cult of North Korea's Kim dynasty have been damaged as isolated pockets of resistance begin to grow, according to reports. A statue of Kim Jong-suk, former leader Kim Jong-il's mother, in Hoeryong, North Hamgyong Province was damaged in October and a monument in Pyongyang was destroyed in April last year.

Based on information from domestic and foreign intelligence agencies, Saenuri Party lawmaker Yoon Sang-hyun said on Sunday, "The Kim Jong-un regime has witnessed several events challenging the authority of regime founder Kim Il-sung and his family."

A door of Mangyongdae, regime founder Kim Il-sung's birthplace in Pyongyang, was stolen in February last year. Mangyongdae is the most sacred place in the North. Minister of People's Security Ju Sang-song, the closest aide to Kim Jong-il, was suddenly fired in March, presumably taking the blame for this case.

In September last year, graffiti reading "Hereditary succession is betrayal of socialism!" and "Down with Kim Jong-un!" were found at major universities and in market areas.

A North Korean receives a ration of fish in Sariwon, North Hwanghae Province, ahead of the 70th birthday of dead leader Kim Jong-il on Thursday, in this footage released by [North] Korean Central TV on Sunday. /KCTV-Yonhap

A source familiar with North Korean affairs said, "Public security agencies were in an uproar in June last year after graffiti denouncing the Kim dynasty were found in some places at universities." Right after the incidents, the regime closed major universities for 10 months.

"On the surface, the regime said it closed the schools to mobilize students for various kinds of construction projects before it would declare the North a 'powerful and prosperous nation.' But in fact, the regime intended to prevent students from creating a disturbance," the source added.

Since a botched currency reform in late 2009, an increasing number of people have openly complained about the regime's excessive policies. In many cases, market traders gesticulated at officials and shouted at them in resistance to attempted crackdowns. Some officials were beaten or even killed. Several cases of arson and attacks on public buildings took place in July last year.

"Dissident activities are still continuing," Yoon said. "This shows that ordinary people's loyalty to Kim Jong-un is still weak, although he has a relatively solid grip on the ruling elite."

Economic difficulties and a growing income gap have led to increasing complaints from people, said Prof. Cho Dong-ho of Ewha Womans University.

Another speculation is that recent public activities by Kim Jong-un indirectly reflect the serious situation he faces. "Kim Jong-il refrained from engaging in public activities until 100 days after Kim Il-sung's death. But Kim Jong-un started visiting military units just 15 days after his father's death," a South Korean security official said. "This implies that he can't afford to lose a day trying to ensure the loyalty of soldiers.”

But the resistance shows no signs of being organized. The attacks are scattered and sporadic and are not seen in Pyongyang.

A South Korean government official said, "The regime has no problem maintaining itself even if there is some resistance, as long as the three- or four-tier surveillance structure and control network built by Kim Il-sung and Kim Jong-il over their lifetime is in place."

There have been isolated incidents of protest before. In October 1991, one arm of a Kim Il-sung statue in Sinuiju was cut off, and in December 1994 a large Kim Il-sung portrait was burned in a factory in Sinuiju. In April 1997, and a tower commemorating Kim Il-sung at a shipyard in Wonsan was destroyed.