Image caption Kim Jong-un (foreground) paid his respects on Monday

North Korean state media have been reporting pledges of loyalty to new leader Kim Jong-un after the death of his father Kim Jong-il.

The body of Kim Jong-il is lying in state in the capital Pyongyang as organised public mourning continues in streets and halls.

State media hailed the new leader, 27, as "the outstanding leader of our party, army and people".

The US has urged North Korea to pursue a "path of peace".

The UK's consul in Pyongyang, Barnaby Jones, said foreign diplomats had been greeted by Kim Jong-un, seeming to confirm that he is indeed now in charge.

But as the choreographed Stalinist-style succession plays out, the still unanswered question is how tight a grip the young untested new leader has on the levers of power, the BBC's John Sudworth reports from the South Korean capital Seoul.

Kim Jong-il died on Saturday of a heart attack caused by overwork and stress at the age of 69, state media said. He will be buried on 28 December.

'Lighthouse of hope'

Kim Jong-un led a solemn procession of mourners on Tuesday past the body of his father, displayed on a bier under glass in a hall of the mausoleum where the embalmed body of Kim Il-sung is kept.

State media heaped praise on the "Great Successor", describing him as a "lighthouse of hope" for a country awash in a "sea of tears and grief."

At the scene All over Pyongyang you can see separate, kind of, mourning events. Outside one major meeting hall, hundreds of people are lining up to go and stand in front of the portrait of the deceased Gen Kim Jong-il. They cry and wail for a few minutes before they are moved along so that the next group can come up. This kind of thing is going on all over the city and there is also a strong sense of mourning, in that the normal activity of shops and the normal way that people might drink, or eat, or enjoy themselves is basically discouraged during this period. In pictures: Kim Jong-il in state Neighbours on alert Regional concerns World media review The strange world of North Korea

"We will look up to the respected Comrade Kim Jong-un as we pledged to do so in front of you," said Lee Jin-Hyang, a worker at the Pyongyang Textile Factory, addressing Kim Jong-il's remains.

Pak Chol Yong, a soldier, was quoted by the state news agency as saying: "We will devotedly safeguard Gen Kim Jong-un with arms, closely rallied as one in mind around him."

Photographs released by North Korean state media showed solemn gatherings in halls and opens 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.

Rafael Wober, a journalist with the Associated Press, one of the few foreign media organisations to be given access to Pyongyang, described the moment news of the death broke on Monday:

"Well, the announcement came as a complete surprise. I went out, I could see immediately in the corridors hotel staff crying, in the restaurant and the shop downstairs, hotel staff in tears, sobbing."

One defector who now lives in Seoul remembered similar scenes in 1994, following the death of the country's founder, Kim Il-sung, and was suspicious of the emotions on display.

"You couldn't not cry in public so people used to pinch themselves to make themselves cry," he said.

Urgent talks

North Korea Image caption North Korean leader Kim Jong-il had suffered from poor health since his stroke in 2008 Population about 23 million

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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 in the internationally isolated nuclear-armed state.

The worry is that Kim Jong-un, less than 30 years old and a completely unknown quantity, may lack the political skill to hang on to power. A power struggle with other family members or the military elite is a worrying possibility, our correspondent says.

US Secretary of State Hillary Clinton has said the US is ready to help the North Korean people and create lasting security on the Korean peninsula.

Around the region, countries have been holding urgent talks about what the implications of Mr Kim's death might be.

South Korea, whose military has been put on alert in the wake of Mr Kim's death, has sent its condolences to the North Korean people.

Its failure to express condolences after the death of Kim Il-sung in 1994 affected relations between the two states for years.