More than five million North Koreans have so far turned out to pay their respects to late leader Kim Jong-il, state media say.
The body of Mr Kim is lying in state in the capital Pyongyang as organised public mourning continues in streets and halls around the country.
His son and presumed heir, Kim Jong-un, has publicly led funeral proceedings.
State media hailed the new ruler as "the outstanding leader of our party, army and people".
Kim Jong-il died on Saturday of a heart attack at the age of 69, say state media reports, which blamed "overwork and stress". He will be buried on 28 December.
The BBC's John Sudworth in Seoul says the figure of five million mourners given by North Korea's state run news agency is impossible to verify.
If true, it would mean more than a fifth of the population had joined in the public grieving in the isolated, nuclear-armed state.
Photographs released by North Korean state media show solemn gatherings in halls and open spaces in Pyongyang.
At least some of the mass wailing and weeping on the streets of Pyongyang is an expression of genuine grief, our correspondent says.
North Korean state media have been reporting pledges of loyalty to the new leader Kim Jong-un after the death of his father.
Kim Jong-un conducted a procession of senior officials viewing the late leader's body, which is displayed in a glass coffin.
He also received mourners, including foreign envoys, indicating a strengthening of his image as the country's political face at home and abroad.
However, two days after Kim Jong-il's death was announced, governments in the region are continuing to debate the implications of his inexperienced youngest son taking power.
Kim Jong-il had been in the process of formalising Kim Jong-un as his successor when he died.
But the transition had not been completed and analysts fear Mr Kim's death could trigger a period of instability.
Speculation is rife about whether the younger Kim can manage to take charge of the country unchallenged.
The Reuters news agency quotes an unnamed source with links to Pyongyang as saying that Kim Jong-un has the full backing of the military.
However, a shift to a more collective form of rule is expected, the source told Reuters, in contrast to the autocratic leadership of Kim Jong-il.
Reuters says its source declined to be identified, but has correctly predicted events in the past.
Firm information is impossible to obtain about what is going on in the closed circles of North Korea's ruling elite.
Activists in South Korea, including North Korean defectors have launched large balloons across the frontier towards the North carrying tens of thousands of propaganda leaflets.
The documents criticise the hereditary transfer of power and also describe the uprisings in the Arab World.
"We will not sit idle while witnessing North Koreans suffer from oppression and hunger under autocratic leadership," one of the organisers, Park Sang-hak, told Yonhap news agency.
Similar leaflet drops in the past have angered Pyongyang.
One topic of discussion among governments in the region is likely to be the apparent failure of intelligence gathering.
For more than 48 hours between the North Korean leader's death and the official announcement it seems no spy agency had the slightest inkling that anything was up, says our correspondent.
The South Korean military has backed the assessment of the country's intelligence chief that Kim Jong-il's special train was not in motion at the time North Korean officials say he died.
The head of South Korean intelligence told parliament on Tuesday that the train was stationary at a Pyongyang station, contradicting claims by North Korea that he died on a moving train.
Analysts say the circumstances of Kim's death could be sensitive to the North Korean leadership because of the way they wish to represent his legacy.
The South Korean military has been put on alert in the wake of Mr Kim's death and the country has sent its condolences to the North Korean people.
"I hope North Korea will overcome this well and peace on the Korean Peninsula will be maintained," said the South Korean President Lee Myung-bak.
Seoul's failure to express condolences after the death of Kim Il-sung in 1994 affected relations between the two states for years.